Question 1

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

Accepted Answer

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

Question 2

Write the name for Sr₃(PO₄)₂.

Accepted Answer

Sr₃(PO₄)₂ is named strontium phosphate because it contains strontium ions (Sr²⁺) and phosphate ions (PO₄³⁻).

Question 3

Identify the compound with covalent bonds.

Accepted Answer

The compound CH₄ has a combination of carbon and sulfur atoms, which typically form covalent bonds. The other options (Kr, KBr, Li, NaCl) are made up of metal and non-metal elements, which typically form ionic bonds.

Question 4

Combustion analysis of an unknown compound containing only carbon and hydrogen produced 0.2845 g of CO₂ and 0.1451 g of H₂O.What is the empirical formula of the compound?

Accepted Answer

The answer of Combustion analysis of an unknown compound containing...

Question 5

Methane and oxygen react to form carbon dioxide and water.What mass of water is formed if 0.80 g of methane reacts with 3.2 g of oxygen to produce 2.2 g of carbon dioxide?

Accepted Answer

The given balanced chemical equation is:
CH4 + 2O2 → CO2 + 2H2O

The molar mass of methane is 16.05 g/mol.
The molar mass of oxygen is 32.00 g/mol.
The molar mass of water is 18.02 g/mol.
The molar mass of carbon dioxide is 44.01 g/mol.

Using the given masses of methane and oxygen, we can calculate the limiting reactant:

No. of moles of CH4 = 0.80 g / 16.05 g/mol = 0.050 mol
No. of moles of O2 = 3.2 g / 32.00 g/mol = 0.100 mol

Since the ratio of CH4 : O2 required for the reaction is 1:2, it is clear that oxygen is the limiting reactant and methane is in excess.

No. of moles of CO2 produced = 2.2 g / 44.01 g/mol = 0.050 mol
No. of moles of H2O produced = 0.050 mol x 2 = 0.100 mol

Mass of water formed = No. of moles of H2O x Molar mass of H2O
= 0.100 mol x 18.02 g/mol
= 1.802 g

Therefore, the mass of water formed is 1.8 g, which is closest to option A (1.8 g).

Question 6

Which one of the following is not an empirical formula?

Accepted Answer

The answer of Which one of the following is not...

Question 7

Combustion analysis of 1.200 g of an unknown compound containing carbon,hydrogen,and oxygen produced 2.086 g of CO₂ and 1.134 g of H₂O.What is the empirical formula of the compound?

Accepted Answer

The empirical formula calculation involves converting the masses of CO2 and H2O produced into moles of carbon and hydrogen, respectively. The mass of oxygen in the compound is found by subtracting the masses of carbon and hydrogen from the total mass of the compound. The moles of each element are then divided by the smallest number of moles to find the simplest whole number ratio of the elements in the compound. This leads to the empirical formula CH3O.

Question 8

What does the illustration represent? (Ref: P3e p.78)

Accepted Answer

The illustration shows two different elements, represented by different colors, combining to form a molecule. This indicates a molecular compound.

Question 9

What is the mass of a sample of water (H₂O)containing 3.00 × 10²²H₂O molecules?

Accepted Answer

To calculate the mass of the water sample, we need to use Avogadro's number (6.022 × 10²³ molecules per mole) and the molar mass of water (18.015 g/mol).

Number of molecules in the sample = 3.00 × 10¹² 
Number of moles = (3.00 × 10¹²) / (6.022 × 10²³) ≈ 4.98 × 10⁻¹² mol

Mass of the water sample = (4.98 × 10⁻¹² mol) × (18.015 g/mol) ≈ 9.00 × 10⁻¹¹ g ≈ 0.900 g

Therefore, the best choice is B, with a mass of 0.900 g.

Question 10

Which of the following is a molecular element?

Accepted Answer

Selenium is a molecular element because it can form molecules consisting of multiple atoms of the same element, such as Se8.

Question 11

Which statement is true?

Accepted Answer

An ionic bond is characterized by the transfer of electrons from a metal atom to a nonmetal atom, resulting in the creation of charged particles called ions that are held together by electrostatic attraction. Covalent bonds, on the other hand, involve the sharing of electrons between atoms.

Question 12

What is the coefficient for O₂ when the equation is balance with smallest whole number coefficients? _____ C₄H₁₀ + _____ O₂ = _____ CO₂ + _____ H₂O

Accepted Answer

The balanced equation is 2 C₄H₁₀ + 13 O₂ = 8 CO₂ + 10 H₂O, so the coefficient for O₂ is 13.

Question 13

Aluminum metal reacts with aqueous iron(II)chloride to form aqueous aluminum chloride 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 is:
2Al(s) + 3FeCl2(aq) → 2AlCl3(aq) + 3Fe(s)
Therefore, the stoichiometric coefficient for aluminum is 2.

Question 14

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest,whole-number coefficients? _____ C₂H₆O(l)+ _____ O₂(g)→ _____ CO₂(g)+ _____ H₂O(l)

Accepted Answer

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

Question 15

What is the empirical formula of a substance that contains 2.64 g of C,0.444 g of H,and 3.52 g of O?

Accepted Answer

The answer of What is the empirical formula of a...

Question 16

You are given three solid compounds (A,B,C)with melting temperatures 700^°C,150^°C and 800^°C respectively.Which of these is a molecular solid?

Accepted Answer

A molecular solid is composed of covalently bonded molecules. Solid B has the lowest melting temperature, which suggests that it is the molecular solid. Solids A and C have higher melting temperatures, indicating that they have stronger intermolecular forces such as ionic or metallic bonding.

Question 17

The mass of a He atom is ________.

Accepted Answer

The mass of a helium (He) atom is approximately 6.64 × 10^-24 grams. This is the mass of a single helium atom, which is much smaller than a gram.

Question 18

How many cations are there in 10.0 g of sodium phosphate?

Accepted Answer

First, we need to find the molar mass of sodium phosphate ($Na_3PO_4$). The molar mass is calculated as follows: $3 \times 22.99$ (sodium) + $30.97$ (phosphorus) + $4 \times 16.00$ (oxygen) = $163.94 \, g/mol$. Then, we calculate the number of moles in 10.0 g of sodium phosphate: $10.0 \, g \div 163.94 \, g/mol = 0.061 \, mol$. Since each formula unit of sodium phosphate contains 3 sodium ions ($Na^+$), the total number of cations is $0.061 \, mol \times 3 \times 6.022 \times 10^{23} \, mol^{-1} = 1.10 \times 10^{23}$ cations.

Question 19

What does the illustration represent? (Ref: P3e p.78)

Accepted Answer

The answer of What does the illustration represent? (Ref: P3e...

Question 20

A certain alcohol contains only three elements,carbon,hydrogen,and oxygen.Combustion of a 50.00 gram sample of the alcohol produced 95.50 grams of CO₂ and 58.70 grams of H₂O.What is the empirical formula of the alcohol?

Accepted Answer

The answer of A certain alcohol contains only three elements,carbon,hydrogen,and...

Quiz 3: Molecules, Compounds and Chemical Equations

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

Write the name for Sr₃(PO₄) ₂.

Identify the compound with covalent bonds.

Combustion analysis of an unknown compound containing only carbon and hydrogen produced 0.2845 g of CO₂ and 0.1451 g of H₂O.What is the empirical formula of the compound?

Methane and oxygen react to form carbon dioxide and water.What mass of water is formed if 0.80 g of methane reacts with 3.2 g of oxygen to produce 2.2 g of carbon dioxide?

Which one of the following is not an empirical formula?

Combustion analysis of 1.200 g of an unknown compound containing carbon,hydrogen,and oxygen produced 2.086 g of CO₂ and 1.134 g of H₂O.What is the empirical formula of the compound?

What does the illustration represent? (Ref: P3e p.78)

What is the mass of a sample of water (H₂O) containing 3.00 × 10²²H₂O molecules?

Which of the following is a molecular element?

Which statement is true?

What is the coefficient for O₂ when the equation is balance with smallest whole number coefficients? ___ C₄H₁₀ + _ O₂ = _ CO₂ + ___ H₂O

Aluminum metal reacts with aqueous iron(II) chloride to form aqueous aluminum chloride 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 stoichiometric coefficient for oxygen when the following equation is balanced using the lowest,whole-number coefficients? ___ C₂H₆O(l) + _ O₂(g) → _ CO₂(g) + ___ H₂O(l)

What is the empirical formula of a substance that contains 2.64 g of C,0.444 g of H,and 3.52 g of O?

You are given three solid compounds (A,B,C) with melting temperatures 700^°C,150^°C and 800^°C respectively.Which of these is a molecular solid?

The mass of a He atom is ________.

How many cations are there in 10.0 g of sodium phosphate?

What does the illustration represent? (Ref: P3e p.78)

A certain alcohol contains only three elements,carbon,hydrogen,and oxygen.Combustion of a 50.00 gram sample of the alcohol produced 95.50 grams of CO₂ and 58.70 grams of H₂O.What is the empirical formula of the alcohol?

Quiz 3: Molecules, Compounds and Chemical Equations

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

Write the name for Sr3(PO4) 2.

Identify the compound with covalent bonds.

Combustion analysis of an unknown compound containing only carbon and hydrogen produced 0.2845 g of CO2 and 0.1451 g of H2O.What is the empirical formula of the compound?

Methane and oxygen react to form carbon dioxide and water.What mass of water is formed if 0.80 g of methane reacts with 3.2 g of oxygen to produce 2.2 g of carbon dioxide?

Which one of the following is not an empirical formula?

Combustion analysis of 1.200 g of an unknown compound containing carbon,hydrogen,and oxygen produced 2.086 g of CO2 and 1.134 g of H2O.What is the empirical formula of the compound?

What does the illustration represent? (Ref: P3e p.78)

What is the mass of a sample of water (H2O) containing 3.00 × 1022 H2O molecules?

Which of the following is a molecular element?

Which statement is true?

What is the coefficient for O2 when the equation is balance with smallest whole number coefficients? _____ C4H10 + _____ O2 = _____ CO2 + _____ H2O

Aluminum metal reacts with aqueous iron(II) chloride to form aqueous aluminum chloride 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 stoichiometric coefficient for oxygen when the following equation is balanced using the lowest,whole-number coefficients? _____ C2H6O(l) + _____ O2(g) → _____ CO2(g) + _____ H2O(l)

What is the empirical formula of a substance that contains 2.64 g of C,0.444 g of H,and 3.52 g of O?

You are given three solid compounds (A,B,C) with melting temperatures 700°C,150°C and 800°C respectively.Which of these is a molecular solid?

The mass of a He atom is ________.

How many cations are there in 10.0 g of sodium phosphate?

What does the illustration represent? (Ref: P3e p.78)

A certain alcohol contains only three elements,carbon,hydrogen,and oxygen.Combustion of a 50.00 gram sample of the alcohol produced 95.50 grams of CO2 and 58.70 grams of H2O.What is the empirical formula of the alcohol?

Write the name for Sr₃(PO₄) ₂.

Combustion analysis of an unknown compound containing only carbon and hydrogen produced 0.2845 g of CO₂ and 0.1451 g of H₂O.What is the empirical formula of the compound?

Combustion analysis of 1.200 g of an unknown compound containing carbon,hydrogen,and oxygen produced 2.086 g of CO₂ and 1.134 g of H₂O.What is the empirical formula of the compound?

What is the mass of a sample of water (H₂O) containing 3.00 × 10²²H₂O molecules?

What is the coefficient for O₂ when the equation is balance with smallest whole number coefficients? ___ C₄H₁₀ + _ O₂ = _ CO₂ + ___ H₂O

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest,whole-number coefficients? ___ C₂H₆O(l) + _ O₂(g) → _ CO₂(g) + ___ H₂O(l)

You are given three solid compounds (A,B,C) with melting temperatures 700^°C,150^°C and 800^°C respectively.Which of these is a molecular solid?

A certain alcohol contains only three elements,carbon,hydrogen,and oxygen.Combustion of a 50.00 gram sample of the alcohol produced 95.50 grams of CO₂ and 58.70 grams of H₂O.What is the empirical formula of the alcohol?