Question 1

Sodium metal reacts with water to form aqueous sodium hydroxide and hydrogen gas.Which equation below best describes the balanced equation for this reaction?

Accepted Answer

The equation needs to be balanced with the same number of atoms of each element on both sides of the equation. The balanced equation for the reaction between sodium and water is:

2Na + 2H2O → 2NaOH + H2

This corresponds to answer choice D.

Question 2

What are the coefficients for the following reaction when it is properly balanced?
___nitrogen monoxide + ___carbon monoxide → ___nitrogen +___carbon dioxide

Accepted Answer

To balance the equation, we need to make sure that the number of atoms of each element is equal on both sides. Starting with nitrogen, we have one nitrogen atom on the left side (in nitrogen monoxide) and one nitrogen atom on the right side (in nitrogen gas). To balance carbon, we have one carbon atom on the left side (in carbon monoxide) and two carbon atoms on the right side (in carbon dioxide). Therefore, we need to put a coefficient of 2 in front of carbon monoxide to balance the carbon atoms. This gives us the balanced equation:

2NO + 2CO -> N2 + 2CO2

The coefficients are 2, 2, 1, 2, so the best choice is B.

Question 3

What are the coefficients for the following reaction when it is properly balanced? ___O₂ + ___CH₄→ ___CO₂ + ___H₂O

Accepted Answer

The answer of What are the coefficients for the following...

Question 4

When the equation,___O₂+ ___C₅H₁₂ → ___CO₂ + ___H₂Ois balanced,the coefficient: Of O₂is:

Accepted Answer

The equation can be balanced as follows: 3O₂ + 4C₅H₁₂ → 4CO₂ + 5H₂ + O Therefore, the coefficient of O₂ is 3. Therefore, the answer is D.

Question 5

When the equation __NO₂ + __H₂O + __O₂ → __HNO₃ is balanced,the coefficient of HNO₃ is

Accepted Answer

To balance the equation, we need 4 molecules of NO₂, 3 molecules of H₂O, and 2 molecules of HNO₃. The coefficient of HNO₃ is 2. Therefore, the answer is choice C.

Question 6

Which of the following equations is NOT balanced properly?

Accepted Answer

The equation is not balanced because there are 4 nitrogen atoms on the left side and only 2 on the right side.

Question 7

When the equation,___N₂+ ___H₂ → ___NH₃ is balanced,the coefficient of hydrogen is:

Accepted Answer

To balance this equation, we need to add a coefficient of 2 in front of the hydrogen gas (H2) on the left-hand side of the equation. This gives us 2H₂. On the right-hand side, there are already 2 hydrogen atoms in the NH group, so we don't need to add any coefficients there. Now the equation is balanced, and the coefficient of hydrogen is 2, which corresponds to choice (C).

Question 8

Which of the following is NOT a sign of a chemical reaction?

Accepted Answer

Absorbing light when chemicals are contacted with each other is not a common sign of a chemical reaction. The other options, A, B, and C, are all typical signs that a chemical reaction is taking place.

Question 9

Before a chemical equation can be written,one must know

Accepted Answer

In order to write a chemical equation, one must know the symbols and formulas of all reactants and products. This is because a chemical equation represents a chemical reaction by showing the reactants and products involved, as well as the stoichiometric relationship between them. The atomic mass and molar mass can be used to calculate the stoichiometry, but they are not necessary to initially write the equation. Similarly, the number of moles of reactants and products may not be known until after the equation is written and balanced.

Question 10

When the equation __Ca₃N₂ + __H₂O → __Ca(OH)₂ + __NH₃ is balanced,the coefficient of H₂O is:

Accepted Answer

The answer of When the equation __Ca₃N₂ + __H₂O →...

Question 11

When water is heated,bubbles form in the water.Is this evidence of a chemical reaction? Why?

Accepted Answer

The formation of bubbles when water is heated is a physical change known as boiling. Boiling is a physical process that does not involve a chemical reaction. Therefore, there is no evidence of a chemical reaction occurring.

Question 12

Which of the following compounds is INSOLUBLE?

Accepted Answer

Insoluble compounds are those that do not dissolve easily in water. Magnesium phosphate is one such compound that is not very soluble in water, whereas the other three (magnesium sulfate, magnesium iodide, and magnesium nitrate) are all soluble in water.

Question 13

What are the coefficients for the following reaction when it is properly balanced? ___HCl + ___Mg → ___MgCl₂ + ___ H₂

Accepted Answer

The answer of What are the coefficients for the following...

Question 14

What are the coefficients for the following reaction when it is properly balanced?
___nitric acid + ___sodium hydroxide → ___sodium nitrate + ___water

Accepted Answer

The answer of What are the coefficients for the following...

Question 15

Which of the following is NOT evidence that a chemical reaction has occurred?

Accepted Answer

All of the given options are evidence of a chemical reaction. A color change can indicate a change in chemical composition, solid formation can be a result of the formation of a new compound or a phase change, gas formation can indicate a release of gas as a product of the reaction, and emission of light can indicate a release of energy as a product of the reaction. Therefore, E is not the correct answer as all these options are evidence of a chemical reaction.

Question 16

What are the coefficients for the following reaction when it is properly balanced?
___potassium iodide + ___lead (II)acetate → ___lead (II)iodide +___potassium acetate

Accepted Answer

The balanced chemical equation is 2KI + Pb(C2H3O2)2 → PbI2 + 2KC2H3O2, which means 2 molecules of potassium iodide react with 1 molecule of lead (II) acetate to produce 1 molecule of lead (II) iodide and 2 molecules of potassium acetate.

Question 17

Which of the following statements about balancing reactions is FALSE?

Accepted Answer

Balancing reactions involves adding coefficients to compounds to ensure both sides of the reaction have equal numbers of each atom. However, adding coefficients does not change the type of compounds in the chemical reaction. The type of compounds remains the same before and after balancing the reaction.

Question 18

What are the coefficients for the following reaction when it is properly balanced? ___Na₃PO₄ + ___Ba(NO₃)₂→ ___NaNO₃ + ___Ba₃(PO₄)₂

Accepted Answer

The answer of What are the coefficients for the following...

Question 19

An aqueous solution is:

Accepted Answer

An aqueous solution is a solution in which water is the solvent and another compound is dissolved in it. Therefore, choice D, "water with another compound dissolved in it," is the correct answer.

Question 20

Which of the following compounds is INSOLUBLE?

Accepted Answer

Aluminum sulfide (Al2S3) is insoluble because sulfide (S2-) is a common ion and aluminum is a metal that forms cations (Al3+), making it difficult for the two ions to combine and form a soluble compound.

Quiz 7: Chemical Reactions

Sodium metal reacts with water to form aqueous sodium hydroxide and hydrogen gas.Which equation below best describes the balanced equation for this reaction?

What are the coefficients for the following reaction when it is properly balanced? _nitrogen monoxide + _carbon monoxide → _nitrogen +_carbon dioxide

What are the coefficients for the following reaction when it is properly balanced? _O₂ + _CH₄→ _CO₂ + _H₂O

When the equation,_O₂+ _C₅H₁₂ → _CO₂ + _H₂Ois balanced,the coefficient: Of O₂is:

When the equation NO₂ + H₂O + O₂ → HNO₃ is balanced,the coefficient of HNO₃ is

Which of the following equations is NOT balanced properly?

When the equation,_N₂+ _H₂ → ___NH₃ is balanced,the coefficient of hydrogen is:

Which of the following is NOT a sign of a chemical reaction?

Before a chemical equation can be written,one must know

When the equation Ca₃N₂ + H₂O → Ca(OH) ₂ + NH₃ is balanced,the coefficient of H₂O is:

When water is heated,bubbles form in the water.Is this evidence of a chemical reaction? Why?

Which of the following compounds is INSOLUBLE?

What are the coefficients for the following reaction when it is properly balanced? _HCl + _Mg → _MgCl₂ + _ H₂

What are the coefficients for the following reaction when it is properly balanced? _nitric acid + _sodium hydroxide → _sodium nitrate + _water

Which of the following is NOT evidence that a chemical reaction has occurred?

What are the coefficients for the following reaction when it is properly balanced? _potassium iodide + _lead (II) acetate → _lead (II) iodide +_potassium acetate

Which of the following statements about balancing reactions is FALSE?

What are the coefficients for the following reaction when it is properly balanced? _Na₃PO₄ + _Ba(NO₃) ₂→ _NaNO₃ + _Ba₃(PO₄) ₂

An aqueous solution is:

Which of the following compounds is INSOLUBLE?

Quiz 7: Chemical Reactions

Sodium metal reacts with water to form aqueous sodium hydroxide and hydrogen gas.Which equation below best describes the balanced equation for this reaction?

What are the coefficients for the following reaction when it is properly balanced? ___nitrogen monoxide + ___carbon monoxide → ___nitrogen +___carbon dioxide

What are the coefficients for the following reaction when it is properly balanced? ___O2 + ___CH4 → ___CO2 + ___H2O

When the equation,___O2 + ___C5H12 → ___CO2 + ___H2O is balanced,the coefficient: Of O2 is:

When the equation __NO2 + __H2O + __O2 → __HNO3 is balanced,the coefficient of HNO3 is

Which of the following equations is NOT balanced properly?

When the equation,___N2 + ___H2 → ___NH3 is balanced,the coefficient of hydrogen is:

Which of the following is NOT a sign of a chemical reaction?

Before a chemical equation can be written,one must know

When the equation __Ca3N2 + __H2O → __Ca(OH) 2 + __NH3 is balanced,the coefficient of H2O is:

When water is heated,bubbles form in the water.Is this evidence of a chemical reaction? Why?

Which of the following compounds is INSOLUBLE?

What are the coefficients for the following reaction when it is properly balanced? ___HCl + ___Mg → ___MgCl2 + ___ H2

What are the coefficients for the following reaction when it is properly balanced? ___nitric acid + ___sodium hydroxide → ___sodium nitrate + ___water

Which of the following is NOT evidence that a chemical reaction has occurred?

What are the coefficients for the following reaction when it is properly balanced? ___potassium iodide + ___lead (II) acetate → ___lead (II) iodide +___potassium acetate

Which of the following statements about balancing reactions is FALSE?

What are the coefficients for the following reaction when it is properly balanced? ___Na3PO4 + ___Ba(NO3) 2 → ___NaNO3 + ___Ba3(PO4) 2

An aqueous solution is:

Which of the following compounds is INSOLUBLE?

What are the coefficients for the following reaction when it is properly balanced? _nitrogen monoxide + _carbon monoxide → _nitrogen +_carbon dioxide

What are the coefficients for the following reaction when it is properly balanced? _O₂ + _CH₄→ _CO₂ + _H₂O

When the equation,_O₂+ _C₅H₁₂ → _CO₂ + _H₂Ois balanced,the coefficient: Of O₂is:

When the equation NO₂ + H₂O + O₂ → HNO₃ is balanced,the coefficient of HNO₃ is

When the equation,_N₂+ _H₂ → ___NH₃ is balanced,the coefficient of hydrogen is:

When the equation Ca₃N₂ + H₂O → Ca(OH) ₂ + NH₃ is balanced,the coefficient of H₂O is:

What are the coefficients for the following reaction when it is properly balanced? _HCl + _Mg → _MgCl₂ + _ H₂

What are the coefficients for the following reaction when it is properly balanced? _nitric acid + _sodium hydroxide → _sodium nitrate + _water

What are the coefficients for the following reaction when it is properly balanced? _potassium iodide + _lead (II) acetate → _lead (II) iodide +_potassium acetate

What are the coefficients for the following reaction when it is properly balanced? _Na₃PO₄ + _Ba(NO₃) ₂→ _NaNO₃ + _Ba₃(PO₄) ₂