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.
Which of the following is a correct example of physical change?1. Burning a piece of wood2. Rusting of an object's surface3. Cutting up a piece of paper4. Changing the chemical identity of a substance
Let's talk about physical and chemical changes:
A Physical change is a type of change where the physical properties of matter change. A change of state of matter, change in colour, odour, solubility, etc. all are examples of physical change. During a physical change, neither the composition nor the chemical nature of matter is changed.
A chemical change is a change of materials into another, new materials with different properties and one or more than one new substances are formed. It results when a substance combines with another to form a new substance (synthesis or either decomposes to form more substances).
According to the definitions given, then from the options given the correct example of physical change is 3. Cutting up a piece of paper.
The universal indicator changes color throughout the pH range. How is this indicator produced?
Answer and Explanation:
The color change of a pH indicator is caused due to the dissociation of protons H+. The most common indicators are: phenolphthalein, methyl red, and bromothymol blue, which are used to indicate pH ranges of about 8 to 10, 4.5 to 6, and 6 to 7.5, respectively. For each indicator, phenolphthalein goes from colorless to pink, methyl red goes from red to yellow, and bromothymol blue goes from yellow to blue.
If HCl (aq) is added to a saturated NaCl solution the Na+1 will a. Increase b. Decrease c remain the same
For this question, we have a solution with NaCl, and HCl is added to it, even though we have more Cl- in the solution, in terms of equilibrium this will shift the equilibrium to the left, but in terms of quantity of the sodium ion, it will remain the same, since no sodium was added or took away, letter C
9. You have 500 grams of Cu2S. How many particles are present?
Explanation:
Before we find the number of particles, we have to find the number of moles that are present in 500 g of Cu₂S using the molar mass of it.
molar mass of Cu = 63.55 g/mol
molar mass of S = 32.07 g/mol
molar mass of Cu₂S = 2 * 63.55 g/mol + 1 * 32.07 g/mol
molar mass of Cu₂S = 159.17 g/mol
mass of Cu₂S = 500 g
moles of Cu₂S = 500 g/(159.17 g/mol)
moles of Cu₂S = 3.14 moles
According to Avogadro's Number there are 6.022 *10^23 particles in 1 mol of Cu₂S. Let's use that relationship to find the answer to our problem.
1 mol of Cu₂S = 6.022 * 10^23 particles
number of particles = 3.14 moles * 6.022 *10^23 particles/mol
number of particles = 1.89 *10^24 particles
Answer: There are 1.89 *10^24 particles in 500 g of Cu₂S.
4 Si + S8 --> 2 Si2S4
We usually represent a synthesis like this:
A + B ------> AB
So, when looking at our equation, it is really similar to it
4 Si + S8 ----> 2 Si2S4
We are combining two compounds to get a different one
Which of the following correctly identifies the intermolecular force represented by A and compares its strength relative to the intermolecular force represented by B? A represents London dispersion forces, which are weaker than the force represented by B. A represents hydrogen bonding, which is weaker than the force represented by B. A represents London dispersion forces, which are stronger than the force represented by B. A represents hydrogen bonding, which is stronger than the force represented by B.
Answer
A represents London dispersion forces, which are weaker than the force represented by B.
Explanation
London dispersion, also called van der Waals forces are caused by the distribution of electrons throughout the molecule/atom of the compound. It is the weakest intermolecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles. This force is sometimes called an induced dipole-induced dipole attraction. London forces are the attractive forces that cause nonpolar substances to condense to liquids and to freeze into solids when the temperature is lowered sufficiently.
According to the given chart, the statement which correctly identifies the intermolecular force represented by A and compares its strength relative to the intermolecular force represented by B is: A represents London dispersion forces, which are weaker than the force represented by B.
Hence, the first option is the correct answer.
Answer:A represents London dispersion force which are weaker than the force represented by B
Explanation:
PLEASE HELP - 100 PTS AND BRAINLIEST
Indicate the number of protons, neutrons, and electrons in isolated ions having the following nuclear symbols:
a) 19F1- has ? protons, ? neutrons, and ? electrons.
b) 24Mg2+ has ? protons, ? neutrons, and ? electrons.
c) 56Fe3+ has ? protons, ? neutrons, and ? electrons.
The number of protons, neutrons, and electrons in isolated ions having the following nuclear symbols:
a) ¹⁹F⁻ has 9 protons , 9 neutrons , 10 electrons
b) ²⁴Mg²⁺ 12 protons , 12 neutrons , 10 electrons
c) ⁵⁶Fe³⁺ 26 protons , 26 electrons , 23 electrons
The atomic number of element represent the number of protons present. the no. of electrons is equals to no. of protons for neutral. the difference between mass no. and the atomic no. is equals to the no. of neutrons.
a) The atomic number of Fluorine is 9. for neutral fluorine the no. of proton is 9 , no. of neutron is 9 , no. of electron is 9. negative sign represent one extra electron.
¹⁹F⁻ has 9 protons , 9 neutrons , 10 electrons
b) The atomic number of Mg is 12. + 2 represents that 2 electrons are removed from the neutral Mg.
²⁴Mg²⁺ 12 protons , 12 neutrons , 10 electrons
c) The atomic number of Fe is 26.
⁵⁶Fe³⁺ 26 protons , 26 electrons , 23 electrons
Thus, The number of protons, neutrons, and electrons in isolated ions having the following nuclear symbols:
a) ¹⁹F⁻ has 9 protons , 9 neutrons , 10 electrons
b) ²⁴Mg²⁺ 12 protons , 12 neutrons , 10 electrons
c) ⁵⁶Fe³⁺ 26 protons , 26 electrons , 23 electrons
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What is the balanced equation for "magnesium reacts with phosphorus"
Magnesium reacts with Phosphorus and produce Magnesium phosphide. The equation is:
Mg + P ---> Mg₃P₂
The balanced equation is:
3 Mg + 2 P ---> Mg₃P₂
It need to have the same amount of atoms of each element on both sides of the equation.
Answer: 3 Mg + 2 P ---> Mg₃P₂
Is the bond length shorter for elements that have more bonds in between them. Like would N2 have a shorter bond length than O2Would N2 have a shorter bond length than O2Because N2 has a triple bond?
Covalent bonding
Covalent Bond
-----
Bonds order is the number of chemical bonds between a pair of atoms and indicates the stability of a bond. Bond order and bond length indicate the type and strength of covalent bonds.
Bond order and length are inversely proportional to each other: when bond order is increased, the bond length is decreased.
O2: O=O
N2: N≡N
N2 has a shorter length than O2
Which of the following relates the volume of a gas to the number of molecules of a gas?Group of answer choicesBoyles's lawCharles's lawDalton's lawGrahams's lawAvogadro's hypothesis
Explanation:
Avogadro's hypothesis or Avogadro's law states that two volumes (equal volumes) of any gas at the same temperature and pressure contain the same number of molecules.
Answer: Avogadro's hypothesis
Answer the following question:Reminder R= .0822. If you have 5 moles of a gas at 400 K, what is the pressure if the volume is 15 L?
We are asked to find the pressure of a gas that is in certain conditions. To find it we must assume that there is no interaction between the gas molecules and the gas behaves like an ideal gas, in this way we can apply the ideal gas law that tells us:
[tex]\begin{gathered} PV=nRT \\ P=\frac{nRT}{V} \end{gathered}[/tex]Where,
P is the pressure of the gas
V is the volume of the gas = 15L
T is the temperature of the gas = 400K
n is the number of moles = 5mol
R is a constant = 0.08206 (atm L)//(mol K)
Now, we replace the known data in the equation:
[tex]P=\frac{5mol\times0.08206\frac{atm.L}{mol.K}\times400K}{15L}=11atm[/tex]Answer: The pressure of the gas will be 11 atm
Find the oxidation numbersi) Oxidation number of Pb in PbOj) Oxidation number of O in PbOk) Oxidation number of Pb in PbO2l) Oxidation number of O in PbO2
Answer:
i) The oxidation number of Pb in PbO is +2.
j) The oxidation number of O in PbO is -2.
k) The oxidation number of Pb in PbO2 is +4.
l) The oxidation number of O in PbO2 is -2.
Explanation:
j) We can start from Oxygen since its oxidation number is alway -2 (except in peroxides where it is -1).
i) As we can see the molecule of PbO is neutral, so knowing that Oxygen has an oxidation number of -2, Pb will have an oxidation number of +2 to make the molecule neutral.
l) We can also start with oxygen for PbO2 molecule, as the same in PbO, O has an oxidation number of -2.
k) PbO2 is also a neutral molecule, but in this case, there are 2 Oxygens with oxidation number of -2, so the total negative charge is -4 ((-2)*2), so to make the whole molecule neutral, Pb must have an oxidation number of +4.
I'm a little confused as to what this question is asking of me. (This is a test review question because I have a test soon)
This question asks you to get 5 of Dalton's postulates and analyze them based on current knowledge.
For example, imagine a postulate saying that atoms are indivisible. Based on what is known nowadays, you may agree with the postulate and keep it as it is; or disagree with this postulate and discard it or modify it. Since we already know that atoms are divided into sub-particles such as protons, neutrons, and electrons, this would be the modification for this postulate, in this example.
Besides that, the question suggests that you make a table with 3 columns, being the first one the postulate itself, then the second could be if you would keep, modify or discard; and the third could be the modification if that was the case.
6. What number uniquely identifies an element?
Answer:
atomic number
Explanation:
"The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the number of electrons."
What role does water play in assembling and decomposing polysaccharides?
INFORMATION:
We need to determine the role of the water in assembling and decomposing of polysaccharides
STEP BY STEP EXPLANATION:
To determine it, we need to know the process of decomposing polysaccharides:
Process of decomposing polysaccharides:
Polysaccharides can be broken down, by hydrolysis of the glycosidic bonds between residues, into smaller polysaccharides as well as disaccharides or monosaccharides. Its digestion within the cells, or in the digestive cavities, consists of a hydrolysis catalyzed by digestive enzymes (hydrolases) generically called glycosidases, which are specific for certain polysaccharides and, above all, for certain types of glycosidic bond. Thus, for example, the enzymes that hydrolyze starch, whose bonds are of the type called α(1→4), cannot break down cellulose, whose bonds are of the β(1→4) type, although in both cases the monosaccharide be the same. Glycosidases that digest polysaccharides, which may be called polysaccharides, generally break every other bond, thus releasing disaccharides and leaving other enzymes to complete the job later.
Now, knowing that we can decompose polysaccharides by hydrolysis and using that hydrolysis is
in which the water molecule divides and breaks one or more chemical bonds and its atoms go on to form a union of another chemical species, we can say that water plays the role of divide their molecules and break one or more chemical bonds so that their atoms form a union and the polysaccharides break down into disaccharides or monosaccharides.
ANSWER:
water plays the role of divide their molecules and break one or more chemical bonds so that their atoms form new unions and the polysaccharides break down into disaccharides or monosaccharides.
Convert 8.81 x 10^-3m to nm
Answer:
8.81 x 10⁶ nm.
Explanation:
Remember that 1 m (meter) equals 1 x 10⁹ nm (nanometer), so if we state a rule of three based on this information and the given data:
[tex]\begin{gathered} 1\text{ m }\Rightarrow1\cdot10^9nm \\ 8.81\cdot10^{-3}m\Rightarrow?\text{ nm.} \end{gathered}[/tex]The calculation will look like this:
[tex]8.81\cdot10^{-3}\text{ m}\cdot\frac{1\cdot10^9\text{ nm}}{1\text{ m}}=8.81\cdot10^6\text{ nm.}[/tex]The answer would be that 8.81 x 10⁻³ m equals 8.81 x 10⁶ nm.
How much potential energy does a 20-kg New Year’s Eve ball have at the top of a 100-m-tall pole?
Answer:
First you need velocity. And hight is 10 m. Now the velocity. Let. g = 10m/s. V=mgh. V= 20 . 10. 10. 2000m/s. Now the kinetic energy will be. Ke = 1/2 mv^2.
Given that4 NH3 (g) + 5 O2(g) > 4 NO(g) + 6 H2O(g)If 8.20 moles of NH3 react with sufficient oxygen, how many moles of water should form?1. 6.11 moles2. 12.0 moles3. 22.0 moles4. 8.25 moles5. 15.1 moles
Answer:
[tex]12.3\text{ moles}[/tex]Explanation:
Here, we want to get the number of moles of water that would form
From the equation of reaction, 4 moles of ammonia produced 6 moles of water
However, 8.2 moles of ammonia will produce x moles of water
To get the value of x, we have it that:
[tex]\begin{gathered} \text{ 4 }\times x\text{ = 8.2}\times\text{ 6} \\ x\text{ = }\frac{8.2\text{ }\times6}{4} \\ \text{ x= 12.3 moles} \end{gathered}[/tex]Please help me find the final answer for number six
1.28x10^23 molecules of carbon dioxide are expelled.
1st) It is necessary to write the balanced equation of combustion from sugar:
[tex]C_{12}H_{22}O_{11}+12O_2\text{ }\rightarrow12CO_2+11H_2O[/tex]2nd) We need to look for the molar mass of C12H22O11 and CO2 to make a relation between those values:
- C12H22O11 molar mass: 342 g/mol
- CO2 molar mass: 44 g/mol
3rd) According to the balanced chemical equation, 1 mol of C12H22O11 produces 12 moles of CO2. Using the molar mass of the compound, in grams, 342g of C12H22O11 produces 528 g (44gx12) of CO2.
Now, with a mathematical Rule of Three we can find the amount of CO2 that is produced from 6.06g of C12H22O11:
[tex]\begin{gathered} 342gC_{12}H_{22}O_{11}-528gCO_2 \\ 6.06gC_{12}H_{22}O_{11}-x=\frac{6.06g\cdot528g}{342g} \\ x=9.36gCO_2 \end{gathered}[/tex]4th) Knowing that 6.06g of jolly rancher produces 9.36g of carbon dioxide, and using the Avogadro's number (6.022x10^23 molecules/mol), we can find the molecules of CO2:
[tex]\begin{gathered} 44gCO_2-6.022\cdot10^{23}molecules \\ 9.36gCO_2-x=\frac{9.36gCO_2\cdot6.022\cdot10^{23}molecules}{44gCO_2} \\ x=1.28\cdot10^{23}molecules \end{gathered}[/tex]So, 1.28x10^23 molecules of carbon dioxide are expelled from the combustion of one jolly rancher.
We can write it in just one equation like this:
[tex]6.06g\cdot\frac{528g}{342g}\cdot\frac{6.022\cdot10^{23}\text{molecules}}{44g}=1.28\cdot10^{23}molecules[/tex]And the result will be the same.
The solvent in a collodial system is alsoknown as the [?] phase.ABdispersedparticledispersionmedium
Answer:
[tex]Dispersed\text{ Medium}[/tex]Explanation:
Here, we want to know what the solvent in a colloidal system is called
The solvent is the medium in which we have the solute dissolved
While the solute is called the dispersed phase, the solvent is known as the dispersed medium
Given the balanced equation below:3Cu + 8HNO3 — 3Cu(NO3)2 + 2NO + 4H2OThe total number of grams of Cu neededto produce 188 grams of Cu(NO3)2 is?
Answer
Mass of Cu = 63.7 g
Explanation
Given:
A balanced chemical equation: 3Cu + 8HNO3 — 3Cu(NO3)2 + 2NO + 4H2O
Required: The total number of grams of Cu
Solution
[tex]\begin{gathered} 188\text{ g Cu\lparen NO}_3)_2\text{ x }\frac{1\text{ mole Cu\lparen NO}_3)_2}{187,56\text{ g Cu\lparen NO}_3)_2}\text{ x }\frac{3\text{ mole Cu}}{3\text{ mole Cu\lparen NO}_3)_2}\text{ x }\frac{63,546\text{ g Cu}}{1\text{ mole Cu}} \\ \\ =\text{ 63.7 g Cu} \end{gathered}[/tex]Calculate the mass/volume percent (m/v) of 16.0 g NaCl in 50.0 mL of solution.Express your answer to three significant figures.
Answer
The mass/volume percent = 16/50 x 100% = 32%
Explanation
Given:
Mass of NaCl, m = 16.0 g
Volume of solution, v = 50.0 mL
What to find:
The mass/volume percent.
Solution
The mass/volume percent of the solution can be calculated using the formula below
[tex]Percent\text{ }mass\text{/}volume=\frac{Mass}{Volume}\times100\%[/tex]The mass/volume percent = 16/50 x 100% = 32%
What is the correct form of the equilibrium constant for the reaction of hydrogen and oxygen to form water? The equation is: 2H 2( g) + O 2( g) ⇌ H 2O( g)
The equilibrium constant is given by the ratio between the products and the reactants, where their stoichiometric numbers are exponents.
[tex]K=\frac{\lbrack H_2O\rbrack^2^{}^{}}{\lbrack H_2\rbrack^2\lbrack O_2\rbrack}[/tex]Observe that the molecule H2O must have a coefficient of 2 in order to balance the equation.
• [H2O] is the equilibrium concentration of the product (water).
,• [H2} is the equilibrium concentration of the hydrogen molecule.
,• [O2] is the equilibrium concentration of the oxygen molecule.
If I have an unknown quantity of gas at a pressure of 120 kPa, a volume of 19 liters, and a temperature of 35°C, how many moles of gas do I have? (Convert temperature to K, and do not include the units in the answer)
Answer:
Explanations:
Using the ideal gas equation expressed as:
[tex]PV=\text{nRT}[/tex]P is the given pressure of the gas
V is the volume of the gas
n is the number of moles
R is the gas constant
T is the temperature in Kelvon.
Given the following parameters:
If 129.63grams of aluminum metal is reacted with767.44grams of iron (III) oxide, what mass ofaluminum oxide is likely to form?Reaction: 2Al(s) + Fe2O3(aq)--> Al2O3(aq) + 2Fe(s)
Step 1
The reaction must be written, completed, and balanced:
2Al(s) + Fe2O3(aq) => Al2O3(aq) + 2Fe(s)
----------------------
Step 2
Information provided:
The mass of Al = 129.63 g
The mass of Fe2O3 = 767.44 g
(because of this, the limiting reactant must be determined)
---
Information needed:
The molar masses:
Al) 26.981 g/mol
Fe2O3) 159.69 g/mol
---------------------
Step 3
The limiting reactant:
2Al(s) + Fe2O3(aq) => Al2O3(aq) + 2Fe(s)
By stoichiometry => 1 mole Al = 26.981 g and 1 mole Fe2O3 = 159.69 g
Procedure:
2 x 26.981 g Al --------- 159.69 g Fe2O3
129.63 g Al ---------- X
X = 129.63 g Al x 159.69 g Fe2O3/2 x 26.981 g Al = 383.61 g
(For 129.63 g of Al, 383.61 g of Fe2O3 is needed, but there is 767.44 g of Fe2O3. Therefore, the limiting reactant is the Al and the excess is the Fe2O3)
-----------------------
Step 4
The mass of Al2O3: (molar mass of Al2O3 = 101.96 g/mol)
2Al(s) + Fe2O3(aq) => Al2O3(aq) + 2Fe(s)
2 x 26.981 g Al ------- 101.96 g Al2O3
129.63 g Al ------- X = 244.93 g
Answer: mass of aluminum oxide = 244.93 g
Calculate the [OH−] of each aqueous solution with the following [H3O+].baking soda, 1.7×10−8M
Answer:
The [OH−] is 5.88x10^-7M.
Explanation:
1st) It is necessary to calculate the pH of the solution using the pH formula and replacing the concentration of H3O+:
[tex]\begin{gathered} pH=-log\left[H_3O+\right] \\ pH=-log(1.7×10−8) \\ pH=7.77 \end{gathered}[/tex]Now we know that the pH is 7.77.
2nd) Now we can calculate the pOH of the solution using the relation between pH and pOH:
[tex]\begin{gathered} pH+pOH=14 \\ 7.77+pOH=14 \\ pOH=14-7.77 \\ pOH=6.23 \end{gathered}[/tex]Now we know that the pOH of the solution is 6.23.
3rd) Finally, we can calculate the [OH−] using the pOH formula and replacing the value of pOH:
[tex]\begin{gathered} pOH=-log\left[OH−\right] \\ 6.23=-log\left[OH−\right] \\ 10^{(-6.23)}=\left[OH−\right] \\ 5.88*10^{-7}=\left[OH−\right] \end{gathered}[/tex]So, the [OH−] is 5.88x10^-7M.
In a good scientific experiment, the dependent variable depends on the…Select oneA. Experimental constantsB.independent variableC.experimental errorD.none of these
Answer:
[tex]B:\text{ Independent variable}[/tex]Explanation:
Here, we want to get the variable on which the dependent variable depends on
The dependent variable value is affected by some values which do not depend on other values
These values that are independent of other values are referred to as the independent variable
12. The list below shows four different substances.
1.03
II. Fe
III. NaCl
IV. CO₂
Which of the substances listed contain only one type of atom?
Answer:
Explanation:
1. O3 compound name ozone make up of only one type of atom oxygen.
2. Fe is an element that contain only iron atom.
3. NaCl sodium chloride is a compound that contains 2 types of atoms sodium and chlorine.
4. CO2 carbon dioxide contains one carbon and two oxygen atom.
Only O3 and Fe contain only one type of atom.
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Calculate the volume of 77.58 g of zinc (density=7.000 g/cm³).
Volume of 77.58 g of zinc is calculated as , volume= 11.08 cm^3
What is mass and volume?Mass measures the amount of matter in a substance and SI unit for mass is the kilogram. Volume measures the amount of space that a substance takes up and SI unit for volume is cubic meter. Volume of the object is directly proportional to its mass such that as the volume increases the mass of the object increases.
Given, mass of zinc = 77.58g
We know that density of zinc = 7g/cm^3
1cm^3 of zinc will move 7gm
Let volume be x
x= 77.58/7
Volume = 11.08 cm^3
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How much water must be added to 560 mL of 15M H2SO4 solution to prepare a 3.0M solution?
Answer
The volume of water that must be added = 2240 mL
Explanation
Given:
Initial concentration, C₁ = 15 M
Initial volume of solution, V₁ = 560 mL
Final concentration, C₂ = 3.0 M
What to find:
The volume of water added to 560 mL of 15M H2SO4 solution to prepare a 3.0M solution.
Step-by-step solution:
The solution involves two steps.
Step 1: Calculate the final volume, V₂ of the solution using the dilution formula.
[tex]\begin{gathered} C_1V_1=C_2V_2 \\ \\ 15\text{ }M\times560\text{ }mL=3.0\text{ }M\times V_2 \\ \\ V_2=\frac{15\text{ }M\times560\text{ }mL}{3.0\text{ }M} \\ \\ V_2=\frac{8400\text{ }mL}{3.0} \\ \\ V_2=2800\text{ }mL \end{gathered}[/tex]Step 2: Subtract the initial volume of the solution from the final volume in step 1 to determine the amount of water added.
The volume of water that must be added = V₂ - V₁
The volume of water that must be added = 2800 mL - 560 mL = 2240 mL