Answer:
d) The oxidation number of K in K2SO3 is +1.
e) The oxidation number of S in K2SO3 is +4.
f) The oxidation number of O in K2SO3 is -2.
g) The oxidation number of S in S8 is 0.
Explanation:
In each case, we can use the Periodic Table of Elements to consult the oxidation number of the elements.
d) In this case, K is in the group 1 of the Periodic Table, so it has always an oxidation number of +1.
f) Oxygen (O) always has an oxidation number of -2 (except in peroxides which has -1).
e) Knowing that the molecule of K2SO3 is neutral (the total charge of the molecule is equal 0), we can sum all the charges of the elements in the molecule, to find out which oxidation number has S in this molecule:
[tex]\begin{gathered} K_2SO_3 \\ K\text{ charge: }(+1)*2=+2 \\ O\text{ charge: }(-2)*3=-6 \\ \end{gathered}[/tex]Now we have to sum them and find out the oxidation number of S that will made the total charge of the molecule equal 0:
[tex]\begin{gathered} K_2SO_3 \\ +2\text{ + S oxidation number -6 =0} \\ -4\text{ + S oxidation number =0} \\ -4+4=0 \end{gathered}[/tex]So, the oxidation number of S is +4.
g) Finally, in this case, the oxidation number of S in S8 is 0, because it is a pure compound.
What is the %v/v when 17.8mL is Acetic Acid is dissolved in 40.8mL of water?
Answer:
30.4 %.
Explanation:
Let's see the volume percentage (% v/v) formula:
[tex]Percent\text{ volume=}\frac{volume\text{ of solute}}{volume\text{ of solution}}\cdot100\text{ \%,}[/tex]in this case, the solute is acetic acid and the solution is the solute and solvent (which is water). Based on this logic, the volume of solute is 17.8 mL, whereas the volume of solution is the sum of the volumes of solute and solvent ( 17.8 mL + 40.8 mL = 58.6 mL), so we just have to replace the values that we have in the formula:
[tex]\begin{gathered} Percent\text{ volume=}\frac{17.8\text{ mL}}{58.6\text{ mL}}\cdot100\%, \\ \\ Percent\text{ volume=30.4\%.} \end{gathered}[/tex]The answer would be 30.4 %.
For the reaction 2NOBr→2NO2+Br2, the rate law is rate =k[NOBr]^2. If the rate of a reaction is 6.5×10−6molL−1s−1, when the concentration of NOBr is 2×10−3molL−1.What would be the rate constant of the reaction?
Answer:
k = 1.625 mol⁻¹ L s⁻¹
Explanation:
What is given?
rate = 6.5 x 10⁻⁶ mol L⁻¹s⁻¹,
[NOBr] = 2 x 10⁻³ mol L⁻¹.
Step-by-step solution:
We want to find the rate constant, k of the reaction based on the rate law:
[tex]rate=k\cdot\lbrack NOBr]^2,[/tex]so we just have to solve for 'k' and replace the given values:
[tex]\begin{gathered} k=\frac{rate}{\lbrack NOBr]^2}, \\ \\ k=\frac{6.5\cdot10^{-6\text{ }}mol\text{ L}^{-1}s^{-1}}{(2\cdot10^{-3}\text{ mol L}^{-1})^2}, \\ \\ k=1.625\text{ mol}^{-1}L^s^{-1} \end{gathered}[/tex]The answer would be k = 1.625 mol⁻¹ L s⁻¹
Which of the following minerals is the most resistant to being scratched?
Hematite
Calcite
Orthoclase
Garnet
3 Cu + 8HNO3 g 3 Cu(NO3)2 + 2 NO + 4H₂O
In the above equation how many moles of NO can be made when 75 moles of HNO3 are
consumed?
As per the given statement 0.297mol NO can be made when 75 moles of HNO3 are consumed
What is HNO3?The inorganic substance with the formula HNO3 is nitric acid. It is a mineral acid that is quite corrosive. The substance is colourless, but older samples have a tendency to have a yellow cast because of breakdown into nitrogen oxides..
'3 Cu + 8HNO3 3 Cu(NO3)2 + 2 NO + 4H₂O
Element Molar Mass
Hydrogen 1
Nitrogen 14
Copper 63.5
Oxygen 16
Referring the above table we get no of moles in HNO3
1(1.0) + 1(14) + 3(16) = 1 + 14 + 48 = 63 g/mol
75g HNO3 x 1 mol HNO3/63 g HNO3 = 1.190 mol HNO3
The coefficient of HNO3 is 8, and NO is 2
1.190 mol HNO3 x 2 mol NO/8 mol HNO3 = 0.297mol NO
Hence, 0.297mol NO can be made when 75 moles of HNO3 are consumed.
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37.In the compound MgO, what is the oxidation number of oxygen?Select one:a. +4b. +2c. +1d. -2
When we have to determine the oxidation number of compounds, we need to look at their specific and most common charges in their non neutral form, and Oxygen is an element that will usually present a -2 oxidation number and charge, the same way Hydrogen will almost always present a charge of +1, these fixed values for some elements is helpful for us to determine the oxidation number of other elements. For oxygen is -2, therefore letter D
CH3OH-water interactions: What happens when the CH3OH molecules are surrounded by water molecules? Briefly describe their interaction.
When the CH₃OH molecules are surrounded by water molecules, there are solvent-solute interactions where the solvent water molecules interact with the OH group of the CH₃OH molecules resulting in the dissolution of the molecules in water.
What is solvation?Solvation refers to the interaction between solvent and solute molecules whereby the solvent molecules surround and interact with the polar groups of the solute molecules resulting in the dissolution of the solute in the solvent.
Solvent-solute interactions are common when polar or ionic substances are dissolved in water. For example, when, methanol, CH₃OH is dissolved in water.
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Which of the following statements is FALSE:O Density is a measure of how closely packed the atoms of a substance are.O The Density of a substance can change if its location changes.O The Density of steel is greater than the Density of cotton.O To calculate the Density of an object we must know its mass
Answer
The Density of a substance can change if its location changes.
Explanation
All the statements are TRUE except
The Density of a substance can change if its location changes.
This is because density is an intensive property, that is regardless of the object's shape, size, or quantity, the density of that substance will always be the same. Even if you cut the object into a million pieces, they would still each have the same density.
Therefore, the statement that is FALSE is
The Density of a substance can change if its location changes.
what type of bonding results from the force of attraction between positively and negatively charged ions?
ANSWER
Ionic bonding
EXPLANATION
Ionic bonding is also known as electrovalent bond, this is a type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound
The charge are always negative and positive charge.
Therefore, the type of bonding is called ionic bonding
Calculate the [H+] given a pH of 2.80
Answer:
The [H+] is 1.6x10^-3 M.
Explanation:
1st) We can calculate the concentration of H+, using the pH formula:
[tex]\begin{gathered} pH=-log\lbrack H^+\rbrack \\ 2.80=-log\lbrack H^+\rbrack \\ 10^{(-2.80)}=\lbrack H^+\rbrack \\ 1.6*10^{-3}M=\lbrack H^+\rbrack \end{gathered}[/tex]So, the [H+] is 1.6x10^-3 M.
A balloon is filled with a 0, gas and has a volume of 179mL at 2.00 atm pressure. What will its volume be if thepressure is changed to 5.50 atm?A) 29.2 mLB) 65.1 mLC) 17.9 mLD) 83.0 ml
In this case, we can use the Boyle's law to solve this problem:
[tex]P1\cdot v1=P2\cdot v2[/tex]We already know the values of P1, v1 and P2 and we have to find v2. Replace for the given values and solve for v2:
[tex]\begin{gathered} 179ml\cdot2.00atm=5.50atm\cdot v2 \\ v2=\frac{179ml\cdot2.00atm}{5.50atm} \\ v2=65.1ml \end{gathered}[/tex]The correct answer is B) 65.1ml.
11. Balance the following acid/base reaction: __Ca(OH)2 + __H2CO3 --> __CaCO3 + __H2O
Given the unbalanced acid/base reaction expressed as:
[tex]aC_{}a\mleft(OH\mright)_2+bH_2CO_3\longrightarrow cCaCO_3+dH_2O[/tex]The equation is balanced if the number of moles of element at the reactant is equal to that of the product.
Next is to determine the values of the constants a,b, c, and d by equating the number of moles of the element on both sides.
For the Calcium element:
a = c .................................. 1
For the Oxygen element
2a + 3b = 3c + d ......................... 2
For the Hydrogen element
2a + 2b = 2d
a + b = d .......................... 3
For the carbon element
b = c ....................... 4
Substitute equation 1 and 4 into 3 to have:
c + c = d
2c = d
d = 2c ...................... 5
Substitute equations 1, 4, and 5 into the unbalanced equation to have:
[tex]cC_{}a(OH)_2+cH_2CO_3\longrightarrow cCaCO_3+2cH_2O[/tex]Cancel out the constant "c" from both sides of the equation to have:
[tex]\begin{gathered} \cancel{c}C_{}a(OH)_2+\cancel{c}H_2CO_3\longrightarrow\cancel{c}CaCO_3+2\cancel{c}H_2O \\ C_{}a(OH)_2+H_2CO_3\longrightarrow CaCO_3+2H_2O \end{gathered}[/tex]This gives the balanced chemical equation
if 2.00 moles of aluminum nitrate are dissolved to form 2.00l of solution , the concentration of the NO3 ion will be ?
First, we write the reaction to solve this:
Al(NO₃)₃(aq) => Al³⁺(aq) + 3NO₃⁻(aq)
We need to calculate the concentration of the salt:
Molarity = moles of Al(NO₃)₃ / Volume of solution (L)
Molarity = 2.00 moles / 2.00 L = 1.00 mol/L
The salt is completely disociated, so the concentration of NO3- ion is:
Concentration NO3- = 3 x Concentration of the salt = 3 x 1.00 mol/L = 3.00 mol/L
Answer: 3.00 mol/L
What type of model that is a smaller or larger copy of an
object and one that shows key features or interactions?
A. mathematical model
B. physical model
C. conceptual model
D. statistical model
A physical model is a replica that has been built that is intended to represent the original object. A physical model may be the same size as the real object it represents, smaller, or larger. A scale model is one that is either bigger or smaller than the real thing.
A physical model is a streamlined tangible depiction of an object or phenomenon that has to be studied, typically on a smaller scale.
The model can replicate the relevant physical factors (temperature, waves, speed, etc.) and forecast the unique limits of the circumstance. Before starting the last stages of a project, these constraints can be considered, tested, and solutions implemented.
Urban planning, naval construction, aeronautics, and other fields involving geometry, thermodynamics, and fluid mechanics frequently use physical models.
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4. Calculate the pH of 0.90M HPO4?Ka HPO4^2- = 4.5 x 10-13(a) 7(b) 14(c) 12.3(d) 8.20(e) 6.20
Answer
Explanation
Given:
[H⁺] = 0.90 M
Ka HPO₄²⁻ = 4.5 x 10⁻¹³
I need to see how to do 2 and 3
Answer:
Explanation:
a) Here, we want to get the limiting reactant
The limiting reactant forms less of the product
From the equation of reaction:
4 moles of aluminum gave 2 moles of product
0.32 mol will give x moles of product:
4 * x = 0.32 * 2
x = 0.16 moles
3 moles of oxygen gave 2 moles of product
0.26 mol will give x moles of product
3 * x = 0.26 * 2
x = 0.173 moles
That means that aluminum is the limiting reagent
b) From the question:
6.38 * 10^-3 mol oxygen gives x mol of product
3 moles of oxygen gives 2 moles of product
To get x:
[tex]x\text{ = }\frac{6.38\times10^{-3}\times2}{3}\text{ = }0.00213\text{ mole}[/tex]For aluminium, we do same process:
[tex]x\text{ = }\frac{9.15\times10^{-3}\times2}{4}\text{ = 0.004575 mole}[/tex]c) From the mass available, we need to get the number of moles that could be produced from each
To get the number of moles, we have to divide the mass by the atomic mass of the element
For Aluminium, the atomic mass is 27 amu
That means the number of moles is:
[tex]\frac{3.17}{27}\text{ = 0.1174 mole}[/tex]Now, from the equation of reaction:
4 moles aluminum gave 2 moles oxygen
0.1174 mole aluminum will give:
[tex]\frac{0.1174\times2}{4}\text{ = 0.0587 mole}[/tex]For oxygen, the atomic mass is 16 amu
For molecular oxygen, we have the molar mass as 32g/mol
The number of moles that will react is thus:
[tex]\frac{2.55}{32}\text{ = 0.0796875 mole}[/tex]From the equation of reaction:
3 moles of oxygen gave 2 moles of product,
0.159375 mole will give:
[tex]\frac{0.0796875\times2}{3}\text{ = 0.053125 mole}[/tex]Since the number of moles from oxygen is lesser, it translates to a lesser amount of product and that makes oxygen the limiting reactant in this case
Answer question number 13. The question is in the image.
Answer: One carbon atom can make a maximum of 4 covalent bonds. The best option to answer the question is number 4.
Explanation:
The question requires us to choose, among the options given, which one corresponds to the maximum number of carbon bonds that can be formed by one carbon atom.
To answer this question, we can consider the electronic configuration of a carbon atom. Carbon (C) presents atomic number 6, therefore it contains 6 electrons and its electronic configuration can be written as:
[tex]1s^22s^22p^2[/tex]Note that there are 4 electrons in carbon's valence shell (2s2 and 2p2), thus a carbon atom needs additional 4 electrons to achieve stability.
If the atom needs 4 electrons to achieve stability, it means it can make 4 covalent bonds to "acquire" these electrons.
Therefore, the best option to answer the question is number 4.
Ammonia, NH3 , reacts with oxygen to form nitrogen gas and water.
4NH3(aq)+3O2(g)⟶2N2(g)+6H2O(l)
What is the percent yield of the reaction?
The percent yield of the reaction when 3.85g of Ammonia reacts with 5.78g of O2 to give out 0.750L of nitrogen is 27.43%
It is given that the mass of Ammonia is 3.85g and the mass of Oxygen is 5.78g. The yield of Nitrogen is 0.750L. To find the percent yield, we need to know the number of moles of ammonia and Oxygen.
No of moles of Oxygen = 5.78/31.99
No moles of Oxygen= 0.181 mol of O2.
No. of moles of Ammonia = 3.85/17.03
= 0.226 mol of NH₃
It can be seen that 0.226 mol of NH₃ reacts with 3/4th of 0.226 mol of O₂ which is 0.1695 mol of O₂.
But the given moles of O₂ are more than that of the required value. Therefore, NH₃ is the limiting reactant and O₂ is the excess.
Therefore,
0.226 mol of NH3 x 2 mol of N₂/ 4 mol of NH3
= 0.113 mol of N₂
Experimentally it would be calculated as
n = PV/RT
n = (1 x 0.750)/(0.0821x295)
n = 0.031 mol of N₂
Percent yield = Experimental yield/theoretical yield x 100
Percent yield= (0.031/0.113)x100
Percent yield= 27.43%
Therefore, the percent yield of N₂ is 27.43%
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Match the type of radiation to a correct description of it.BetaAlphaGamma?Decreases the atomic number of the atom.?Increases the atomic number of the atom.?Does not change the atomic number of the
ANSWER
Alpha particle...........> decreases the atomic number of an atom
Beta particles .............> increases the atomic number of the atom
Gamma particle ..........> does not change the atomic number of the atom
EXPLANATION
The three types of radioactive particles are;
1. Alpha particle
2. Beta particle
3. Gamma particle
Alpha particles has a positive charge with atomic number 2 and mass number 4
Any atom that gives off alpha particle, will have it atomic number drops by 2 and its mass number drops by 4
Hence, alpha particle decreases the atomic number of an atom
Beta particles; The atomic number of a beta particle changes, it can either be positive or negative
When an atom gives off a beta particle, the mass number number of the atom remains unchanged but the atomic number increases
Hence, beta particles increases the atomic number of the atom
Gamma particle is a neutral particle and it does not have any charge on it
When an atom gives off a gamma particle, the mass and atomic numbers of the atom remain unchanged
Hence, gamma particle does not change the atomic number of the atom
Nitrogen dioxide reacts with water to produce nitric acid and nitrogen monoxide. How many grams of nitric acid can be prepared from 95.52 grams of nitrogen dioxide?
87.22grams
Explanations:The chemical reaction between Nitrogen dioxide and water to produce nitric acid and nitrogen monoxide is expressed as:
[tex]3NO_2+H_2O\rightarrow2HNO_3+NO[/tex]Determine the moles of nitrogen dioxide(NO2)
[tex]\begin{gathered} mole=\frac{mass}{molar\text{ mass}} \\ mole=\frac{95.52}{46.0055} \\ mole\text{ of NO}_2=2.076moles \end{gathered}[/tex]According to stoichiometric ratio, 3 moles of nitrogen dioxide produces 2moles of nitric acid, the moles of nitric acid required is expressed as;
[tex]\begin{gathered} moles\text{ of }HNO_3=\frac{2}{3}\times2.076 \\ moles\text{ of }HNO_3=1.384moles \end{gathered}[/tex]Determine the mass of nitric acid
[tex]\begin{gathered} mass\text{ of HNO}_3=mole\times molar\text{ mass} \\ mass\text{ of HNO}_3=1.384\times63.01 \\ mass\text{ of HNO}_3=87.22grams \\ \end{gathered}[/tex]Hence the mass of nitric acid required is 87.22grams
C*(UPQuestion 6 of 26šiWhich of the following sets of quantum numbers is not allowed?A) n = 1, l = 0, ml = 0B) n = 4, f = 0, ml = -1C) n = 3, l = 1, ml = 0D) n = 2,1 = 0, ml = 0E) n = 3, l = 2, ml = -2
Let's analyze option B:
Given that n=4, l=0 and ml=-1, we could draw:
If we have n=4, l=0, that means that the electron configuration ends at 4s. As you can notice, "s" orbital can only adquire one pair of electrons and ml can only be 0. In the answer option this is -1, so this option is not correct.
The answer is B.
Properties:large brittle crystalhigh MPthigh BPtnon-conductorThe properties above would best describe a solid held together by.....ionic bondscovalent bondsintermolecular forces
In general, ionic compounds have the following characteristics:
• They are solid at room temperature;
,• Its atoms arrange themselves in such a way as to produce a crystalline lattice (a crystal).
,• They are soluble in water;
,• They are capable of performing the phenomenon of dissociation (ion release) when they undergo fusion, that is, when they change from the solid state to the liquid state, or when they are dissolved in water;
,• They have high melting and boiling points;
,• They have shine;
,• They conduct current when dissolved in water or after undergoing the melting process.
,• Non-conductor at solid state.
Covalent compounds have the following characteristics:
• Physical State at Room Temperature: Under ambient conditions, molecular and covalent compounds are found in three physical states (solid, liquid, and gas).
,• Melting and Boiling Point: In general, the melting and boiling points of these substances are lower than those of ionic substances.
,• Electric current: In their pure forms, both liquids and solids do not conduct electric current.
,• Solubility: Polar dissolves into polar and non-polar dissolves into non-polar.
,• Tenacity: The resistance of covalent substances to impact or mechanical shock is low.
,• In general, they are brittle solids, as shown in the case of glass, which is formed by sodium and calcium silicates.Hardness: In general, they have high hardness.
With this in mind...
Answer: ionic bonds
How is electroplating done?
A. The anode is replaced by the object to be electroplated.
B. A precipitation reaction is used to plate the cathode with an ion.
OC. The metals in the anode and cathode electrodes trade positions.
OD. Ions of one metal are reduced onto a cathode made of a different
metal.
The process of electroplating is done as follows:
Ions of one metal are reduced onto a cathode made of a different
metal; option D is correct.What is electroplating?Electroplating is the process by which one metal is used to coat the surface of another metal.
Electroplating is done in order to improve the appearance of one metal and is also done in order to protect against corrosion.
The process of electroplating involves electrolysis.
The metal to be coated over the is used as the anode while the metal to be coated is used as the cathode.
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Laboratory balances that measure to the hundredths (0.01g) are calleda) centigram balanceb) milligram balancec) analytical balance
Answer:
[tex]A[/tex]Explanation:
Here, we want to select the balance used to measure mass to a hundredth accuracy
The kind of balance used in this case is the centigram balance. The measure the mass of a substance to an accuracy of a hundredth which is 0.01g
The options for this question are vaporizing, condensing, freezing, and melting but I’m not sure where to put them. If anyone could help it would be greatly appreciated
Physical states are different in compounds if we have a change of temperature or pressure, and in certain temperatures we can see a compound undergo a physical change, going from solid to liquid or gas, and the reverse is also possible, as we will see now:
If liquid is turning into solid, then we have a freezing situation
Liquid to solid will be known as melting
Gas to liquid will be known as condensing
Liquid to gas will be known as vaporizing
Which of these characteristics would most help a city make long-term road
and infrastructure plans?
O A. Age structure
OB. Birthrate
C. Growth rate
OD. Death rate
The characteristics that would help a city to be able to make long term infrastructural plans is the growth rate. Option C
What is infrastructure?The term infrastructure has to do with the facilities that are put up in a city to aide life in a city. It is the process of development in a city that helps a city to be able to aide the inhabitants to live a comfortable life.
It is very important to see that there is a laid down plan for the development of a city or a place and this is very essential to the development of the place and the better life of the people that live in the city.
Now, the infrastructural plans that are made in a city has to factor in the growth rate of the city and this have to be based on the projected growth rate.
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Name each of the following Acids and Bases:Mg(OH)2
ANSWER
Mg(OH)2 is a base
STEP-BY-STEP EXPLANATION:
Firstly, we need to define the word "acid and base"
An acid is a substance that will produce hydrogen ion as the only positive ion when dissolved in water
WHILE
A base is a substance that can neutralize the acid by reacting with hydrogen ions to produce salt and water. A base also contain hydroxyl ion (OH)
From the above definition, you will see that Mg(OH)2 is a base
what is the mass of aluminum used if 0.1 moles of aluminum chloride is produced by reacting aluminium with an acid
The mass of aluminum used if 0.1 moles of aluminum chloride is produced by reacting aluminum with an acid is 2.69 g.
given that :
number of moles of aluminum chloride = 0.1 moles
The balanced reaction is given as :
2Al + 6HCl -----> 2AlCl₃ + H₂
it is clear from the reaction that:
2 moles of Al produce 2 moles of AlCl₃
the mole ratio is 2 : 2
mean moles of Al = 0.1
molar mass of Al = 26.9 g/ mol
mass of Al = number of moles × molar mass
= 0.1 × 26.9
= 2.69 g
Thus, The mass of aluminum used if 0.1 moles of aluminum chloride is produced by reacting aluminum with an acid is 2.69 g.
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what is functional group?write the functional group ofalcoholesteracid hydridealdehyde and mention an example of each compound containing these functional group
EXPLANATION:
A functional group is a collection of atoms within molecules that bind together to react in predictable ways.
The functional group tell us how a compound react and, also, the chemical properties of such compound
Below are the functional group of some compound
Alcohol
The functional group of alcohol is ---- OH
Example: Ethanol
Ester
The functional group of Ester is --O--
Example: Ethyl ethanoate
Aldehyde
The functional group of aldehyde is
Example: Vanillin
A mixture of krypton and neon gas is compressed from a volume of 79.0L to a volume of 71.0L, while the pressure is held constant at 17.0atm. Calculate the work done on the gas mixture. Round your answer to 2 significant digits, and be sure it has the correct sign (positive or negative).
Using the fact that:
[tex]W=P\Delta V[/tex]We could replace our values as follows:
[tex]\begin{gathered} W=17atm\cdot(71L-79L) \\ W=17atm\cdot(-8L) \\ W=-136J \end{gathered}[/tex]As you can see, the work done is negative since the gas is being compressed. Therefore,
The work done is -136J.
In kJ, the answer is -0.136kJ. Rounded to 2 significant digits, this is -0.14kJ
What type(a) of interparticle forces exist between molecules in a pure sample of CH2F2? A) induced dipole attractionsB) dipole-dipole forcesC) H-bonding
This molecule will have dipole-dipole forces.
Answer: B