Chemical Equations And Reactions

1. Which of the following reactions involves the ions of two compounds exchanging places to form two new compounds?

Synthesis reaction

Single-replacement reaction

Double-replacement reaction

Combustion reaction

AX + BY --> AY + BX

Explanation

AX + BY --> AY + BX

2. According to the law of conservation of matter, the total mass of all the reacting substances is -

More than the mass of all the products

More than the total mass of all the products and reactants

Less than the total mass of all the products

Equal to the mass of all the products

Matter cannot be created or destroyed, it is conserved.

Explanation

Matter cannot be created or destroyed, it is conserved.

3. Which of the following reactions involves one element replacing an element in a compound that is from the same activity series?

Combustion reaction

Decomposition reaction

Single-replacement reaction

Double-replacement reaction

If only one element is being replaced, it is a single-replacement reaction.

Explanation

If only one element is being replaced, it is a single-replacement reaction.

4. Which of the following reactions involves a single compound producing two or more simpler substances?

Synthesis reaction

Decomposition reaction

Combustion reaction

Double-replacement reaction

When you have a single substance breaking down into simpler substances, it is decomposing.

Explanation

When you have a single substance breaking down into simpler substances, it is decomposing.

5. Which equation represents a precipitation reaction?

Equation A

Equation B

Equation C

Equation D

A precipitation reaction is one that produces a solid. Look at the symbols for the products.

Explanation

A precipitation reaction is one that produces a solid. Look at the symbols for the products.

6. Which of the following reactions involves two or more substances combining to form a new compound?

Single-replacement reaction

Synthesis reaction

Decomposition reaction

Combustion reaction

The substances are combining to make something new. This is the definition of a synthesis reaction.

Explanation

The substances are combining to make something new. This is the definition of a synthesis reaction.

7. What would you observe during a precipitation reaction?

Gas bubbles are produced.

A solid settles out.

There is a color change.

The test tube warms.

A precipitation reaction produces a solid.

Explanation

A precipitation reaction produces a solid.

8. When an acid decomposes, what are the products?

Non-metal oxides and a salt

Non-metal oxides and water

Metal oxides and oxygen

Metal oxides and peroxide

H2SO4 --> SO3 + H2O

Explanation

H2SO4 --> SO3 + H2O

9. Predict the products of this reaction.

Na2CO3

Na + CO3

NaCO2 + O2

NaC + O3

Sodium is the only metal, so there is no single-replacement reaction. Think about a balanced equation.

Explanation

Sodium is the only metal, so there is no single-replacement reaction. Think about a balanced equation.

10. Which coefficients are required to correctly balance the equation?

1,2,3,2

2,5,4,2

2,4,5,2

2,3,5,2

Make sure each type of atom is equal on both sides.

Explanation

Make sure each type of atom is equal on both sides.

11. Predict the outcome of the reaction where zinc metal is added to a solution of potassium chloride.

No reaction occurs

Gaseous zinc is formed

Potassium calcide forms

Zinc chloride forms

Zinc is below potassium in the Activity Series so it would not replace potassium.

Explanation

Zinc is below potassium in the Activity Series so it would not replace potassium.

12. By predicting the outcome of the following reactants mixing together in an aqueous solution, what type of reaction will take place?

Double-replacement reaction

Synthesis reaction

Decomposition reaction

Single-replacement

You can tell by looking at the reactants that this is set up as AX + BY --> . This indicates a double-replacement reaction.

Explanation

You can tell by looking at the reactants that this is set up as AX + BY --> . This indicates a double-replacement reaction.

13. A student performing an investigation of chemical reactions mixes two aqueous solutions and observes a change in color. Color change is most indicative of which type of chemical reaction?

Neutralization

Precipitation

Oxidation-reduction

Acid-base

Neutralization and acid-base are pretty much the same thing. There may not be any color change with this reaction. A precipitation reaction will turn cloudy, but not necessarily a color change. A color change usually indicates an oxidation-reduction reaction. Think about a nail rusting.

Explanation

Neutralization and acid-base are pretty much the same thing. There may not be any color change with this reaction. A precipitation reaction will turn cloudy, but not necessarily a color change. A color change usually indicates an oxidation-reduction reaction. Think about a nail rusting.

14. After the correct formula for a reactant in an equation has been written, the -

Chemical formula cannot be altered

Subscripts of the formula are changed to balance the equation

Chemical symbols in the formula must appear only on the reactant side

Same chemical formula must be written on the product side of the equation

Remember that if you alter the chemical formula, you have changed the substance.

Explanation

Remember that if you alter the chemical formula, you have changed the substance.

15. Which equation represents a neutralization reaction?