Question 1

Which represents one formula unit?

Accepted Answer

A formula unit is the simplest whole-number ratio of the atoms in a compound. For H, H2, and NaH, the formula unit is one atom of each element.

Question 2

Which contains Avogadro's number of formula units?

Accepted Answer

C

Question 3

1.00 mole of O₂ contains the same number of molecules as

Accepted Answer

1 mole of any substance contains Avogadro's number of molecules, so 1 mole of O2 has the same number of molecules as 1 mole of CH3CO2H.

Question 4

What is the sum of the coefficients when the following equation is balanced using the lowest whole-numbered coefficients? _____ PH₃(g)+ _____ O₂(g)→ _____ P₄O₁₀(s)+ _____ H₂O(g)

Accepted Answer

To balance this equation, we need to start by balancing the phosphorus (P) atoms, which requires placing a coefficient of 2 in front of the PH₃(g) compound. Next, we balance the oxygen (O) atoms by placing a coefficient of 13 in front of the O₂(g) compound. This gives us: 2PH₃(g) + 13O₂(g) → _____P₄O₁₀(s) + _____H₂O(g) Now we can balance the sulfur (S) atoms by placing a coefficient of 10 in front of the P₄O₁₀(s) compound and a coefficient of 10 in front of the H₂O(g) compound. This gives us: 2PH₃(g) + 13O₂(g) → 10P₄O₁₀(s) + 10H₂O(g) The sum of the coefficients is 2+13+10+10 = 35, but we are only interested in the coefficients of the reactants (PH₃(g) and O₂(g)), which add up to 2+13 = 15. Therefore, the answer is C: 19 (which is obtained by adding up the coefficients of the reactants and the product containing them).

Question 5

What is the molar mass of calcium permanganate?

Accepted Answer

The answer of What is the molar mass of calcium...

Question 6

What is the molar mass of Co(NO₃)₂?

Accepted Answer

The molar mass of Co(NOS)₂ is calculated as follows: Cobalt (Co) = 58.93 g/mol, Nitrogen (N) = 14.01 g/mol, Oxygen (O) = 16.00 g/mol, and Sulfur (S) = 32.07 g/mol. The formula Co(NOS)₂ includes 1 Co, 2 N, 2 O, and 2 S. Adding these gives: 58.93 + (2*14.01) + (2*16.00) + (2*32.07) = 58.93 + 28.02 + 32.00 + 64.14 = 183.09 g/mol, which rounds to 183 g/mol.

Question 7

Which one of the following statements about balanced equations is false?
In a balanced reaction

Accepted Answer

In a balanced chemical equation, it is the atoms of each element that must be balanced on both sides of the reaction arrow, not necessarily the molecules. The focus is on ensuring that the same number of each type of atom appears on both sides of the equation, reflecting the law of conservation of mass. The statement about molecules needing to be balanced is misleading because the same number of molecules of a given substance does not need to be present on both sides of the equation; rather, it is the individual atoms within those molecules that must be balanced.

Question 8

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest whole-number coefficients _____ C₃H₈O(l)+ _____ O₂(g)→ _____ CO₂(g)+ _____ H₂O(l)

Accepted Answer

The answer of What is the stoichiometric coefficient for oxygen...

Question 9

Aluminum metal reacts with iron(II)sulfide to form aluminum sulfide and iron metal.What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

Accepted Answer

The balanced chemical equation for the reaction between aluminum metal (Al) and iron(II) sulfide (FeS) is:

2Al + 3FeS → Al2S3 + 3Fe

This equation shows that 2 moles of aluminum react with 3 moles of iron(II) sulfide to form 1 mole of aluminum sulfide and 3 moles of iron. Therefore, the stoichiometric coefficient for aluminum is 2. Choice B is the correct answer.

Question 10

What is the sum of the coefficients when the following equation is balanced using the lowest whole-numbered coefficients? _____ B₂O₃(s)+ _____ HF(l)→ _____ BF₃(g)+ _____ H₂O(l)

Accepted Answer

The given equation is a chemical reaction that needs to be balanced. The equation involves elements with subscripts indicating their isotopic composition, which is not standard for balancing chemical equations. The sum of coefficients in a balanced chemical equation depends on the stoichiometry, which cannot be determined from the given isotopic notation without a clear chemical formula. Therefore, the correct answer is "none of these" because the question does not provide a standard chemical equation to balance.

Question 11

What is the molar mass of aspartic acid,C₄O₄H₇N?

Accepted Answer

To calculate the molar mass of a compound, we need to add up the atomic masses of all the atoms present. Aspartic acid has the following chemical formula: C4H7NO4. Adding up the atomic masses of each atom, we get:
C(4) + H(7) + N(1) + O(4) = 12.011(4) + 1.008(7) + 14.007 + 15.999(4) = 133 g/mol. Therefore, the correct answer is C.

Question 12

1.00 mole of O₂ contains the same number of oxygen atoms as

Accepted Answer

One mole of any substance contains Avogadro's number (6.02 x 10^23) of particles. O₂ has 1 oxygen atom per molecule, therefore 1 mole of O₂ contains 6.02 x 10^23 oxygen atoms. A) 0.667 mole of O₃ would contain (0.667) x (6.02 x 10^23) = 4.01 x 10^23 oxygen atoms. O₃ has 1 oxygen atom per molecule, therefore this would also require 4.01 x 10^23 molecules of O₃. However, 1 mole of O₃ contains (10 + 1 + 13) = 24 atoms per molecule, meaning that 0.667 mole of O₃ only contains (0.667) x (6.02 x 10^23) x 24 = 9.67 x 10^23 atoms total. Thus, answer A is incorrect. B) 1.00 mole of CH₃CO₂H would contain (1.00) x (6.02 x 10^23) = 6.02 x 10^23 molecules. Each molecule contains 1 oxygen atom, so there are also 6.02 x 10^23 oxygen atoms. Thus, answer B is correct. C) 2.00 mole of CH₃CH₂OH would contain (2.00) x (6.02 x 10^23) = 1.20 x 10^24 molecules. Each molecule contains 1 oxygen atom, so there are also 1.20 x 10^24 oxygen atoms. Thus, answer C is correct. Therefore, the best choice(s) are D, as both B and C are correct.

Question 13

Which is a formula mass?

Accepted Answer

Formula mass is the mass of one formula unit of a compound. A formula unit is the simplest whole-number ratio of atoms or ions in a compound. The formula mass of a compound is the sum of the atomic masses of all the atoms in the formula unit. The correct choices are B) 2)0 amu of H₂ and C) 24.0 amu of NaH.

Question 14

Which one of the following statements about balanced equations is true? A reaction is balanced by

Accepted Answer

Balancing an equation involves adjusting the coefficients in front of each molecule or ion to ensure that the number of atoms of each element is the same on both the reactant and product side. Changing the charge on an ion (A) or rearranging atoms in a molecule (D) would alter the identity of the species involved in the reaction and create an entirely different reaction. Changing the formula of a molecule (B) would also create a different reaction. Therefore, the only appropriate method for balancing an equation is to multiply by suitable coefficients (C).

Question 15

Which conducts electricity?

Accepted Answer

A large collection of iron atoms conducts electricity because the atoms are arranged in a lattice structure that allows electrons to move freely, whereas a single iron atom does not have this structure.

Question 16

Given the chemical equation: N₂ + 3 H₂ → 2 NH₃.On a molecular level,what do the coefficients mean?

Accepted Answer

The answer of Given the chemical equation: N₂ + 3...

Question 17

Given the chemical equation: N₂ + 3 H₂ → 2 NH₃.On a macroscopic level,what do the coefficients mean?

Accepted Answer

The coefficients in a chemical equation represent the mole ratios of the reactants and products. Therefore, option B is the correct choice as it states that one mole of nitrogen reacts with three moles of hydrogen to give two moles of ammonia. Options A and C are incorrect as they refer to individual atoms or molecules rather than moles. Option D may be true but it is not the best choice as B is the most specific and accurate option.

Question 18

Chemical equations are balanced in order to obey the law of

Accepted Answer

Chemical equations must obey the law of mass conservation, which states that the total mass of reactants must equal the total mass of products in a chemical reaction. Balancing the equation ensures that mass is conserved. The law of definite proportions and the law of multiple proportions refer to the ratios of elements in compounds, while mass action refers to the kinetic behavior of a reaction.

Question 19

Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid.What is the stoichiometric coefficient for sulfuric acid when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

Accepted Answer

The answer of Calcium phosphate reacts with sulfuric acid to...

Question 20

What is the molar mass of hydrogen gas?

Accepted Answer

The molar mass of hydrogen gas (H₂) is 2.00 g/mol because it consists of two hydrogen atoms, each with an atomic mass of approximately 1.00 g/mol.

Quiz 3: Formulas, equations, and Moles

Which represents one formula unit?

Which contains Avogadro's number of formula units?

1.00 mole of O₂ contains the same number of molecules as

What is the sum of the coefficients when the following equation is balanced using the lowest whole-numbered coefficients? ___ PH₃(g) + _ O₂(g) → _ P₄O₁₀(s) + ___ H₂O(g)

What is the molar mass of calcium permanganate?

What is the molar mass of Co(NO₃) ₂?

Which one of the following statements about balanced equations is false? In a balanced reaction

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest whole-number coefficients ___ C₃H₈O(l) + _ O₂(g) → _ CO₂(g) + ___ H₂O(l)

Aluminum metal reacts with iron(II) sulfide to form aluminum sulfide and iron metal.What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

What is the sum of the coefficients when the following equation is balanced using the lowest whole-numbered coefficients? ___ B₂O₃(s) + _ HF(l) → _ BF₃(g) + ___ H₂O(l)

What is the molar mass of aspartic acid,C₄O₄H₇N?

1.00 mole of O₂ contains the same number of oxygen atoms as

Which is a formula mass?

Which one of the following statements about balanced equations is true? A reaction is balanced by

Which conducts electricity?

Given the chemical equation: N₂ + 3 H₂ → 2 NH₃.On a molecular level,what do the coefficients mean?

Given the chemical equation: N₂ + 3 H₂ → 2 NH₃.On a macroscopic level,what do the coefficients mean?

Chemical equations are balanced in order to obey the law of

Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid.What is the stoichiometric coefficient for sulfuric acid when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

What is the molar mass of hydrogen gas?

Quiz 3: Formulas, equations, and Moles

Which represents one formula unit?

Which contains Avogadro's number of formula units?

1.00 mole of O2 contains the same number of molecules as

What is the sum of the coefficients when the following equation is balanced using the lowest whole-numbered coefficients? _____ PH3(g) + _____ O2(g) → _____ P4O10(s) + _____ H2O(g)

What is the molar mass of calcium permanganate?

What is the molar mass of Co(NO3) 2?

Which one of the following statements about balanced equations is false? In a balanced reaction

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest whole-number coefficients _____ C3H8O(l) + _____ O2(g) → _____ CO2(g) + _____ H2O(l)

Aluminum metal reacts with iron(II) sulfide to form aluminum sulfide and iron metal.What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

What is the sum of the coefficients when the following equation is balanced using the lowest whole-numbered coefficients? _____ B2O3(s) + _____ HF(l) → _____ BF3(g) + _____ H2O(l)

What is the molar mass of aspartic acid,C4O4H7N?

1.00 mole of O2 contains the same number of oxygen atoms as

Which is a formula mass?

Which one of the following statements about balanced equations is true? A reaction is balanced by

Which conducts electricity?

Given the chemical equation: N2 + 3 H2 → 2 NH3.On a molecular level,what do the coefficients mean?

Given the chemical equation: N2 + 3 H2 → 2 NH3.On a macroscopic level,what do the coefficients mean?

Chemical equations are balanced in order to obey the law of

Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid.What is the stoichiometric coefficient for sulfuric acid when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

What is the molar mass of hydrogen gas?

1.00 mole of O₂ contains the same number of molecules as

What is the sum of the coefficients when the following equation is balanced using the lowest whole-numbered coefficients? ___ PH₃(g) + _ O₂(g) → _ P₄O₁₀(s) + ___ H₂O(g)

What is the molar mass of Co(NO₃) ₂?

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest whole-number coefficients ___ C₃H₈O(l) + _ O₂(g) → _ CO₂(g) + ___ H₂O(l)

What is the sum of the coefficients when the following equation is balanced using the lowest whole-numbered coefficients? ___ B₂O₃(s) + _ HF(l) → _ BF₃(g) + ___ H₂O(l)

What is the molar mass of aspartic acid,C₄O₄H₇N?

1.00 mole of O₂ contains the same number of oxygen atoms as

Given the chemical equation: N₂ + 3 H₂ → 2 NH₃.On a molecular level,what do the coefficients mean?

Given the chemical equation: N₂ + 3 H₂ → 2 NH₃.On a macroscopic level,what do the coefficients mean?