An atom with 6 bonds without a lone pair of electrons gives an octahedral molecular shape using the VSEPR rules.
What is VSPER Theory?
Based on the number of valence shell electron bond pairs between the atoms in a molecule or ion, the valence shell electron pair repulsion (VSEPR) hypothesis is a model used to predict 3-D molecular shape. According to this hypothesis, electron pairs will position themselves to reduce the consequences of their mutual repulsion. The electron pairs are, in other words, as far apart as they can be.
For forecasting and visualising molecular structures, utilise the VSEPR model. Linear, trigonal planar, angled, tetrahedral, trigonal pyramidal, trigonal bipyramidal, disphenoidal (seesaw), t-shaped, octahedral, square pyramidal, square planar, and pentagonal bipyramidal are the different types of structures.
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The leaves of the electroscope repelled each other when given a negative charge. Do you think it would be possible to get the leaves of the electroscope to attract each other? Explain.
No it would not work because an insulator stops electrons from moving from moving to atom to atom so there is no way to get a charge to the metal leaves
What is metal leaf electroscope ?
Gold leaf electroscop has two gold leafs suspended from a metal(usually brass) stem in a vacuumed glass jar and connected to a metal cap. The glass is grounded with the help of a metal foil to make it uncharged. It can be used to:
Detect charge: Body under test is touched with the metal cap. If the leaves diverge, the body is charged and if there is no effect on leaves, then the body is uncharged.
To identify the nature of charge: The electroscope is charged by a known body(say positively charged body) and then the body is removed. Next, the body under test is brought in contact with the metal cap. If the leaves diverge further, the body has same charge(positive) and if the leaves come closer to each other, the body has opposite charge(negative).
Identify a body as conductor or insulator: Take two electroscopes. Charge one of the electroscopes so that its leaves will diverge. Then, connect the two electroscopes by the object under test. If the leaves of other electroscope diverge, the body is a conductor and if there is no effect on the electroscopes, the body is an insulator.
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which amino acid contains sulfur atoms that form covalent disulfide bonds and stabilize the tertiary structure of some proteins?
Cysteine, amino acid contains sulfur atoms that form covalent disulfide bonds and stabilize the tertiary structure in some proteins.
What are Amino acids?Organic substances known as amino acids are primarily made up of nitrogen, carbon, hydrogen, and oxygen. Twenty distinct amino acids are required by your body for growth and optimal operation. All 20 of them are crucial for your health, but only 9 are considered to be absolutely necessary.
What are proteins?Organic molecules called proteins are found in all living things. They perform a wide range of tasks, such as transportation, organizing, and defence. Proteins have up to four different layers of structure and are made up of chains of amino acids.
What are Disulfide bonds?An S- anion from one sulfhydryl group acts as a nucleophile, attacking the side chain of a second cysteine to create a disulfide bond, and in the process releases electrons (reducing equivalents) for transfer. Disulfide bond formation involves a reaction between the sulfhydryl (SH) side chains of two cysteine residues.
Hence, cysteine, amino acid contains sulfur atoms that form covalent disulfide bonds and stabilize the tertiary structure in some proteins.
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Which of the following is a sign that a chemical change has occurred?
Group of answer choices
glass changes shape when it falls and breaks
water produces a gas when it is placed on a hot stovetop
a firework explodes releasing heat, sound, and light energy
a substance becomes cold when it is placed in the freezer
The change that represents a chemical change is; a firework explodes releasing heat, sound, and light energy
What is a chemical change?We define a chemical change as one in which there is the alteration of the reactants and the products. The chemical bonds in the reactants and the products are broken up in a chemical change.
This is why we can say that when there is a chemical change, there would be the formation of a new substance and then there could be some markers of a chemical change that could take place in the system and these may include but are not limited to;
Appearance of a new color
Change in the temperature
Evolution of a gas
Thus the explosion of the firework is a typical example of the ocurence of a chemical change .
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This type of bias occurs when researchers fail to choose a representative sample of potential respondents is called?
The type of bias occurs when researchers fail to choose a representative sample of potential respondents is called sampling bias.
Sampling bias is the phenomenon that occurs when a research take a look at layout fails to collect a representative sample of a goal populace. This happens generally due to the fact that the selection standards for respondents failed to seize a wide enough sampling frame to represent all viewpoints.
Some of the commonplace varieties of sampling bias encompass self-selection bias, nonresponse bias, survivorship bias, pre-screening or advertising bias, and healthful user bias.
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Energy from the_______is constantly passing through the different layers of the atmosphere as waves, landing on and
being absorbed into the Earth's surface to provide the heat and warmth for
life.
A. insolation
B. weather
C. air
D. conduction
E. ozone
F. ecological
G. atmosphere
H. sun
I. convection
J. tilts
Answer:
H.Sun
Explanation:
The heat source for our planet is the Sun. Energy from the sun is transferred through space and through the earth's atmosphere to the earth's surface. Since this energy warms the earth's surface and atmosphere, some of it is or becomes heat energy.
So the answer is H.Sun
How do you calculate moles at STP?
The following formula will calculate the amount of moles at STP: Molar volume at STP (litres)/Volume at STP (litres).
At STP, moles can be converted to gas volume and gas volume to moles using molar volume. The conversion factor is based on the equality 1mol=22.4L. The molar volume of a gas at STP, which is defined as 273.15 K (0°C) and 1 atm, is 22.414 L/mol. 0°C (273.15 K) and 1 atm of pressure are considered standard temperature and pressure (STP). The volume of one mole of a gas at STP is its molar volume. A mole (6.02 1023 typical particles) of any gas at STP takes up 22.4 L of space.
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Give short answers for the following
1. Comment Dalton's atomic theory and the areas in which modifications were
made.
Dalton's atomic theory was having different postulates. Some of them are:
1. All matters are made up of tiny indivisible particles called atoms.
2. All atoms are identical in mass, size and many other properties.
3. Atoms can be neither created nor destroyed.
4. Atoms can be combined or separated from elements.
But all these theories were modified:
1. Atom can further be divided into 3 parts electron, proton and neutron.
2. Isotopes are members of same atoms family but still have different properties. Isotopes are the number which have same atomic number but different mass number. Example Carbon isotopes.
3. This Theory failed for isobars. Isobars are the elements which have different atomic number but same mass number. Example Ar and Ca
4. This theory failed for Allotropes. Allotropes are the member of same family with different properties. Example Diamond and Graphite which are of carbon family.
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What happens when you mix H2SO4 and nacl?
When sulfuric acid and sodium chloride are mixed, a reaction occurs that produces sodium bisulphate and hydrogen chloride.
The chemical equation between sulfuric acid and sodium chloride is
2NaCl + H2SO4 → NaHSO4 + 2 HCl(g)
When concentrated Sulphuric acid (H2SO4) is added to Sodium chloride, the formation of Sodium Bisulfite( NaHSO4 ) and Hydrochloric acid (HCL) will take place.The hydrogen chloride gas is released into the air, and can be harmful to breathe.The sodium sulphate is a solid that is left behind in the container.
In this reaction, concentrated Sulphuric acid acts as a strong oxidising agent and Chloride ion acts as a weak reducing agent. With the help of a strong acid, protonation of ions will take place to form Sodium Bisulphate.
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why does the temperature of the reaction mixture drop (as opposed to remaining constant) once the reaction reaches the stoichiometric point?
The reaction is no longer operating and no longer producing heat, which causes the temperature to drop. Additionally, the temperature of the reactant solution added after the stoichiometric point is achieved is lower than that of the reaction mixture.
What is Stoichiometric Point?
The titration's equivalence point is reached by adding just enough titrant to totally neutralize the analyte solution. The titrant's moles (a standard solution) are equivalent to the moles of the unknown-concentration solution. Because it is at this point that the quantity of acid needed to neutralise an identical amount of base is equal, it is often referred to as the stoichiometric point. Please take note that this does not imply that the acid to base ratio is 1:1. The equation for a balanced acid-base chemical reaction determines the ratio.
Actually at the equivalence point, the titrant and analytes have completely reacted, that's why temperature drop.
The equivalence point, or stoichiometric point, of a chemical reaction is the point at which chemically equivalent quantities of bases and acids have been mixed
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What are the relative positions of the sun, Earth, and moon at the times of lunar and solar eclipses, as well as new, first-quarter, full, and last-quarter phases of the moon?
The relative positions of the sun, Earth, and moon at the times of lunar and solar eclipse is the earth comes in between the moon and the sun.
The relative positions of the sun, Earth, and moon :
1) New moon : they are lined up with the moon comes in between the earth and the sun.
2) first quarter : the first quarter phase is when the earth - moo line is 90 ° away from the earth and sun line.
3) full moon : The moon , the earth and the sun line up and the earth is comes in between the moon and the sun.
4) the last quarter : the the last quarter phase is when the earth moon line is 270° away from the earth sun.
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Write a nuclear equation to describe the neutron-induced fission of Pu-241 to form Kr-89 and Ce-149. Determine how many neutrons are produced in the reaction.
The number of neutrons produced in the reaction is 5.
Neutrons are the neutral particles present in the nucleus of any atom.
Nuclear equation:
2(1)n₀ + (241)Pu -----> (89)Kr + (149)Ce + 3n₀
In balancing nuclear equations- the sums of the superscripts and the subscripts must be the same on each side of the equation.
On Balancing the superscripts, we get:
2 + 241 = 89 + 149 + x
243 = 238 + x
x = 5
The balanced equation is:
2(1)n₀ + (241)Pu -----> (89)Kr + (149)Ce + 5n₀
Therefore, the number of neutrons produced in the reaction is 5.
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if 10.0 g of aluminum reacts with excess sulfuric acid, and 54.2 g of al2(so4)3 are collected, what is the percent yield of al2(so4)3? a) 63.4% b) 85.5% c) 117% d) 47.1% e) not enough information given
The percent yield of al2(so4)3 is option B. 85.58%.
In chemistry, yield, additionally called reaction yield, is a measure of the quantity of moles of a product fashioned in relation to the reactant fed on, acquired in a chemical reaction, generally expressed as a percent.
Percent yield is the percent ratio of real yield to the theoretical yield. it is calculated to be the experimental yield divided through theoretical yield expanded by one hundred%. If the real and theoretical yield are the equal, the percentage yield is one hundred%.
Calculation:-
2Al+3H2SO4 → Al2(SO4)3+3H22
27*2 g of Al produces = 342 g Al2(SO4)3
10 g Al Produces = 342 /54 × 10
= 63.33
percentage yield = 54.2/63.33 × 100
= 85.58%
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the compound of which two elements is most likely to involve covalent bonding? electronegativities of unknown elements q 0.9 x 3.0 r 1.0 z 4.0 t 2.8
The compound of T and X is most likely to involve covalent bonding.
The ability of an atom or functional group to draw electrons to itself is known as electronegativity in chemistry. An atom's electronegativity is influenced by both its atomic number and how far away from its charged nuclei its valence electrons are located.
The differences in the electronegativities are:
Q and Z : 4.0-0.9 = 3.1
R and X : 3.0-1.0 = 2.0
T and Z : 2.8-0.9 = 1.9
T and X : 3.0-2.8 = 0.2
Q and T : 2.8 - 0.9 = 1.9
Smallest difference in electronegativity causes a higher overlap in the orbitals of the shared electrons.
Therefore, the smallest difference between the given elements is between T and X.
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How much amount of NaCl is decomposed by 4.9 g of H2SO4 if 6g of nahso4 and 1.825 g of HCL are produced in the same reaction 6 g 4.9 g 1.825 g 2.925 g?
2.925 g NaCl is decomposed by 4.9 g of H2SO4. If 6g of nahso4 and 1.825 g of HCL are produced in the same reaction
We have to find out how much amount of NaCl is decomposed in reaction,Where we have given mass of reactant and product as follow;
Mass of H2SO4 = 4.9g
Mass of NaHSo4 = 6g
Mass of HCL = 1.825g
The reaction can be given as:
NaCl + H2SO4 → NaHSO4 + HCl
According to law of conservation of mass:
W(NaCl) + W(H2SO4) = W(NaHSO4) + W(HCl)
W(NaCl) + 4.9g = 6g + 1.825g
W(NaCl) = 6+1.825−4.9
W(NaCl) = 2.925 g
So, 2.95 g of NaCl is Decomposed by H2SO4 during reaction.
What is the law of conservation of mass?
It states that all chemical equations must be balanced because matter cannot be created or destroyed in chemical reactions. Mass of Reactant and Mass of product after reaction are always same.
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In an electrolytic cell the electrode at which the electrons enter the solution is called the ______ ; the chemical change that occurs at this electrode is called _______.
An electrolyte is a substance that dissolves in water to yield a solution that conducts electricity
An electrolyte is a substance that dissolves in water and produces ions that conducts electricity.
What is an electrolyte?An electrolyte can be described as a medium containing ions that are electrically conducting through the movement of ions but not conducting electrons. Most soluble salts, acids, and bases can be dissolved in a polar solvent, such as water. Upon dissolving, the substance dissociates into cations and anions, which disperse throughout the solvent.
The movement of cations and anions in opposite directions within the solution and conduct electricity in a solution such as a hydrogen chloride (HCl), under conditions of high temperature or low pressure, can function as electrolytes.
Electrolyte solutions are formed when salt is placed into a solvent and the individual components separate due to the thermodynamic interactions between solvent and solute, in a process known as "solvation".
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the half life of a certain radioactive sample is 1 hr. if the mass of the sample is 1 gram at noon, what will be the mass of the sample at 3pm?
The half life of a certain radioactive sample is 1 hr. if the mass of the sample is 1 gram at noon, what will be the mass of the sample at 3pm?
The half-life is the time it takes for one-half of the radioactive element to decay. The value of the half-life given here is one hour.
After one hour (1 PM) there would only be
(1/2)*(1 g)= 0.5 g of the element remaining.
After three hours (3 PM) there would only be
(1/2)*(1/2)*(1/2)*(1 g) = (1/8)g remaining.
Half-life is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive. The term is also used more generally to characterize any type of exponential decay.
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What are the 3 types of chemical bond which atoms do they form between?
There are three primary types of chemical bonding such as ionic bond, covalent bond, and metallic bond.
A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules and crystals. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds, or through the sharing of electrons as in covalent bonds. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, ionic and metallic bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the London dispersion force and hydrogen bonding. Strong chemical bonding arises from the sharing or transfer of electrons between the participating atoms.
There are three primary types of bonding: ionic, covalent, and metallic.
An ionic bond is formed when valence electrons are transferred from one atom to the other to complete the outer electron shell.Example of an ionic bond is the formation of sodium fluoride, NaF, from a sodium atom and a fluorine atom.
A covalent bond is formed when the valence electrons from one atom are shared between two or more particular atoms.Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom.
A metallic bond is formed when the valence electrons are not associated with a particular atom or ion, but exist as a "cloud" of electrons around the ion centres.Metallic bonding is especially common in minerals involving transition metals. Gold, silver, and copper are examples of minerals with metallic bonds.
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if an ideal gas initially at 5 bar and 12.5 l is compressed at constant temperature to 2.5 l, what is the final pressure of the gas? g
The final pressure of the gas with initial pressure of 5 bar and initial volume of 12.5 L is 25 bar.
The Boyle's law can be used to explain the pressure-volume relationship of an ideal gas at constant temperature. The final pressure can be easily predicted using the relation as shown below if the beginning pressure and volume of an ideal gas are known at a constant temperature with the final volume.
P1V 1 = P2V 2
P 1 denotes the starting pressure, P2 is the ending pressure, V 1 is the starting volume, and V 2 is the ending volume.
The initial pressure P1= 5 bar
The initial volume V1= 12.5 L
The final volume V2= 2.5 L
The final pressure P2=?
P1V1=P2V2
5×12.5= P2× 2.5
P2= 62.5/2.5
P2= 25 bar
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Which is not found on the periodic table of elements. the atomic number of each element, the rarity of each element, the atomic mass of each element
Answer:
The rarity of each element.
Explanation:
The periodic table shows the atomic number and the atomic mass. The abundance (or rarity) of each element is not given.
Answer: sorry misclick
Explanation:
Why does calcium chloride melt ice the fastest?
Because of the low freezing point of calcium chloride it melts the ice fastest.
The calcium chloride provided a better performance at a lower temperature.
As the decrease in temperature, it dissociates into three ions instead of only two ions. These ion allows a way to the bond of water to get rid of the strong bonds.
Also, the hygroscopic properties of calcium chloride makes it attract the moisture from the surroundings.
The faster brine making ability of calcium chloride allows it to melt the ice faster and also when calcium chloride melt the ice it releases heat.
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what is the relationship among electrons, the octet rule, and the oxidation number of a monatomic ion
The electrons that are shared, lost, or gained are called valence electrons. The charge an ion will have after gaining or losing electrons is indicated by the oxidation number.
According to the octet rule, elements interact with one another to form a noble gas electron configuration by either gaining electrons or losing them. The number of electrons in an element's outermost shell is known as its valency, whereas the number of electrons an element has gained or lost in a compound is known as its oxidation state. The primary distinction between valency and oxidation state is this. Each shell can hold a maximum of half the number of elements in the corresponding period in terms of electrons.
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While attempting to determine the structure of a compound using elemental analysis and functional group tests, you are generally able to recover your original sample.
a. True
b. False
True, You can typically get your original sample back when utilizing functional group tests and elemental analysis to try to figure out a compound's structure.
Which test is applied to a compound's elemental analysis?In an elemental analysis, the sodium test, also known as Lassaigne's test, is used to determine whether certain foreign elements, such as halogens, nitrogen, sulfur, and phosphorus, are present in an organic compound.
What analytical techniques can be used to ascertain a compound's structure?The four primary methods are mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, infrared (IR), and ultraviolet and visible spectroscopy. A minimal amount of sample is required for spectroscopy, and after an IR, NMR, or UV spectrum has been generated, the sample can be reused.
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nmr spectroscopy, or_____magnetic resonance spectroscopy, is a very important tool in the determination of organic structures. this technique relies on the interaction of a particular nucleus with a field followed by absorption of energy of a specific____, depending on the chemical environment of the nucleus.
NMR spectroscopy, or nuclear magnetic resonance spectroscopy, is a very important tool in the determination of organic structures. This technique relies on the interaction of a particular nucleus with a magnetic field followed by absorption of energy of a specific frequency depending on chemical environment of the nucleus.
what is NMR spectroscopy?
NMR spectroscopy can be defined as an indispensable tool which applies magnetic field to an atomic nucleus (e.g., the most common stable isotopes 1H, 13C, 15N) and radio frequency pulses to characterize resonant frequency of that atomic nucleus according to its chemical or environmental surroundings
Nuclear magnetic resonance (NMR) spectroscopy is advanced characterization technique. It is used to determine molecular structure at the atomic level of a sample.learn more about NMR spectroscopy at
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Which are easier for your body to metabolize: saturated or unsaturated fats?
The unsaturated fats are easier for the body to break because they are liquid at room temperature.
What are unsaturated fatty acids?Unsaturated fats, which are liquid at room temperature, are regarded as healthy fats because they help reduce inflammation and raise blood cholesterol levels. Unsaturated fatty acids that have been converted to saturated fatty acids are known as trans fats.
Conversely, saturated fats lack double bonds, while unsaturated fats do. As a result, they take on a kinkier shape and don't pack as tightly. Their bonds are more easily broken when molecules are farther apart.
Therefore, since unsaturated fats are liquid at normal temperatures, the body may more easily break them down.
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ice freezing exothermic or endothermic?
Answer: exothermic reaction
Explanation:When water becomes a solid, it releases heat, warming up its surroundings. This makes freezing an exothermic reaction.
Answer: Exothermic Reaction
Explanation:
Exothermic: Releases heat and causes the temperature of the immediate surroundings to rise.
Endothermic: Absorbs heat and cools the surroundings.
When water becomes a solid, it releases heat, warming up its surroundings. This makes freezing an exothermic reaction.
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examine the melting points as you go down a family and across a period. is there a trend? if there is a trend, what is it? a. down a family: b. across a period
Both the melting and boiling factors lower down the group as the melting points as you go down a family and across a period. is there a trend.
As nicely discovered earlier, the greater delocalised electrons gift and the smaller the radius of the atom, the better the melting factor of the metallic. As we circulate throughout duration three the quantity of delocalised electrons consistent with metallic atom will increase and the radius of the factors decreases. This way the melting factor will increase.
The melting and boiling factors of the Group 1 factors lower on descending the group. This is because of a lower withinside the forces of appeal among the atoms. On crossing a duration withinside the Periodic Table the atomic length decreases. On descending a collection the atomic length will increase.In a duration, the melting and boiling factor first will increase after which decreases.
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you are in a place that is extremely hot and dense. you can't see far because your surroundings are opaque to light. around you, nuclear fusion is converting carbon into oxygen and other elements. where are you?
The expansion of the universe suggests that items were once closer together, because material becomes hotter and denser when it is compressed.
Nuclear fusion is transforming carbon into oxygen and other elements while you are at the center of a big star near the end of its life, which makes it difficult for you to see far because the area is opaque to light around you. Later, in a process known as stellar nucleosynthesis, the heavier elements were produced from hydrogen. This was a prolonged process whereby hydrogen and helium were fused together in the stars, which acted as enormous furnaces, at various points of their lives. The universe had gotten bigger.
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9. A gas sample occupies 3.25 liters at 24.5 °C and 1825 mm Hg. Determine
the temperature at which the gas will occupy 4250 mL at 1.50 atm.
Answer: 243K
Explanation:
how many grams of pbbr2 will precipitate when excess nh4br solution is added to 79.0 ml of 0.546 m pb(no3)2 solution?
The number of moles of HI needed is 0.1234 mol, Mass of PbBr2 is 21.3g , Volume of HI solution needed is 237 ml.
What is precipitate ?
It is common for an insoluble compound to form when a solution having a specific cation (a positively charged ion) is mixed with another solution carrying a specific anion (a negatively charged ion). The solid that divides is referred to as a precipitate.
What is excess solution ?
Reactant or reagent that is still present after a chemical reaction has finished is known as excess reagent. In other words, when a chemical reaction occurs, more of a reactant is present than is needed to complete the reaction.
1) Volume of Pb(NO3)2 solution = 76.0ml = ( 76.0ml) x ( 1L / 1000ml) = 0.0760 L
Number of moles of Pb(NO3)2 reacted = Molarity of Pb(NO3)2 solution x Volume of Pb(NO3)2 solution
= 0.764 molL-1 x 0.0760 L ( here M can be shown as molL-1)
= 0.05806 mol
As NH4Br is mentioned to be present in excess the amount of product PbBr2 depends on Pb(NO3)2
Number of moles of PbBr2 formed = Number of Pb(NO3)2 moles reacted = 0.05806 mol
Mass of PbBr2 = moles of PbBr2 x molar mass of PbBr2
= 0.05806 mol x 367 g/mol
= 21.3g
Thus mass of PbBr2 that will precipitate = 21.3g
2) MgCO3 moles = ( mass of MgCO3) / ( molar mass fo MgCO3)
= ( 5.20g / 84.3g/mol) = 0.0617 mol
Number of moles of HI needed = 2 x MgCO3 moles ( based on balanced equation coefficients)
= 2 x 0.0617 mol = 0.1234 mol
Volume of HI solution needed = ( Moles of HI solution needed) / ( Molarity of HI solution)
= ( 0.1234 mol / 0.520molL-1) ( here units M can be shown as molL-1)
= 0.237L
= 0.237L x ( 1000 ml / 1L)
= 237 ml
Thus volume of HI solution needed = 237 ml
Therefore, Number of moles of HI needed is 0.1234 mol, Mass of PbBr2 is 21.3g , Volume of HI solution needed is 237 ml.
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