Chapter 7 Study Guides Zanger

Which of the following is a correctly balanced chemical equation? A. 2H2 + O2 -> 2 H2O B. N2 + 3H2 -> NH3 C. Zn + 2AgNO3 -> Zn(NO3)2 + Ag D. Cu + O -> Cu2O

A. 2H2 + O2 -> 2H2O

Which of the following is a correctly balanced equation describing a synthesis reaction? A. 2H2 + O2 -> 2H2O B. KClO3 -> KCl + O2 C. 3Fe + O2 -> Fe2O3 D. H2CO3 -> H2O + CO2

A. 2H2 + O2 -> 2H2O

Write the chemical formula for Copper (II) Nitrate - Cu (+2) - NO3 (-1) A. Cu(NO3)2 B. Cu2NO3 C. CuNO3 D. Cu2(NO3)2

A. Cu(NO3)2

When a chemical reaction occurs. A. an energy change always occurs B. an energy change occasionally occurs C. energy is always released D. energy is always absorbed

A. an energy change always occurs

When two substances combine chemically, the properties of the products are... A. different from the properties of the reactants B. the same as the properties of the reactants C. a combination of the properties of the reactants D. unpredictable

A. different from the properties of the reactants

A ___ reaction has an energy sign written on the reactant side of the reaction. A. endothermic B. exothermic

A. endothermic

A ___ reaction is a reaction that absorbs energy. A. endothermic B. exothermic

A. endothermic

In Figure B, this chart represents a ___ reaction. <img src="https://lh4.googleusercontent.com/3N6TYVeeIa3hqHwTqq4c19fZaOsnBZ90PJ2J9MM3yS0sE_JjyHeJa22LKj05cw2X4lfaDRseqQ=w685" alt="Captionless Image"/> A. endothermic B. exothermic

A. endothermic

Photosynthesis is an example of a ___ reaction. A. endothermic B. exothermic

A. endothermic

The barium hydroxide & ammonium thiocyanate demo that reacted to freeze the water on the board is an example of a ___ reaction. A. endothermic B. exothermic

A. endothermic

If two substances are chemically combined and there is a release of energy. the reaction is described as A. exothermic B. analytic C. endothermic D. catalytic

A. exothermic

In general, increasing the concentration of reactants causes the reaction to occur. A. faster B. more slowly C. by absorbing energy D. by giving off energy

A. faster

An increase in temperature will usually cause the rate of a chemical reaction to A. increase B. decrease C. remain the same D. become immeasurable

A. increase

Which does not occur as a result of a chemical reaction? A. new atoms may form B. molecules may react with other molecules C. molecules may be broken apart to become atoms D. atoms may join with other atoms or molecules

A. new atoms may form

Cl 2 + NaBr -> NaCl + Br2 A. single replacement B. double replacement C. synthesis D. decomposition

A. single replacement

In a ___ reaction, an element and a compound react to form an element and a compound. A. single replacement B. double replacement C. synthesis D. decomposition E. combustion

A. single replacement

In the formule 5CaSO4, the total number of sulfur atoms present is A. 1 B. 5 C. 4 D. 20

B. 5

Which of the following gives the correct symbols and formulas for the reaction in which magnesium combines with oxygen? Mg (+2) O (-2) A. Mg + O = MgO2 + energy B. Mg + O2 -> MgO + energy C. Mg + O2 = MgO + energy D. Mg + O2 -> MgO2 + energy

B. Mg + O2 -> MgO + energy

Write the formula for Magnesium Phosphate - Mg (+2) - PO4 (-3) A. MgPO4 B. Mg3(PO4)2 C. Mg2(PO4)3 D. Mg3PO8

B. Mg3(PO4)2

Breaking a solid reactant into smaller pieces results in A. a decrease in the surface area B. an increase in the reaction rate C. a decrease in the reaction rate D. a decrease in the number of molecular collisions

B. an increase in the reaction rate

The number that describes how many molecules of a substance are involved in a chemical reaction is a A. valence number B. coefficient C. oxidation number D. subscript

B. coefficient

Ba(NO3)2 + K2SO4 -> BaSO4 + KNO3 A. single replacement B. double replacement C. synthesis D. decomposition

B. double replacement

In a ___ reaction, 2 compounds react to form 2 new compounds. A. single replacement B. double replacement C. synthesis D. decomposition E. combustion

B. double replacement

In an exothermic reaction. A. some energy is destroyed B. energy is released C. energy is taken from the surroundings D. energy is stored in one or more of the products

B. energy is released

A ___ reaction has an energy sign written on the product side of the reaction. A. endothermic B. exothermic

B. exothermic

A ___ reaction is a reaction that releases energy. A endothermic B. exothermic

B. exothermic

Burning or combustion is an example of a ___ reaction. A. endothermic B. exothermic

B. exothermic

In Figure A, this chart represents a ___ reaction. <img src="https://lh4.googleusercontent.com/3N6TYVeeIa3hqHwTqq4c19fZaOsnBZ90PJ2J9MM3yS0sE_JjyHeJa22LKj05cw2X4lfaDRseqQ=w685" alt="Captionless Image"/> A. endothermic B. exothermic

B. exothermic

Combustion or burning... A. is always an endothermic reaction B. is always an exothermic reaction C. may be exothermic or endothermic D. stores energy in the molecules of the reacting substances

B. is always an exothermic reaction

When a chemical reactions occurs,? A. energy is always given off B. new substances are formed C. new atoms are formed D. new atoms and new substances are formed

B. new substances are formed

In the lab that involved the mixing of chemicals, the insoluble substance is called a ___. A. chemical B. precipitate C. solution D. element

B. precipitate

In an endothermic reaction, which of the following contain a greater amount of energy? A. reactants B. products

B. products

Enzymes increase the rate of chemical reactions in the body by A. regulating body temperature B. increasing the surface area of the reactants C. acting as catalysts D. changing the concentration of the reactants

C. acting as catalysts

What information does a chemical equation give about a chemical reaction? A. the kinds of atoms involved in the reaction B. the numbers of atoms involved in the reaction C. both the kinds and numbers of atoms involved in the reaction D. none of these

C. both the kinds and numbers of atoms involved in the reaction

In the chemical reaction 2AlCl3 ---> 2 Al + 3Cl2, the substances Al and Cl2 are A. reactants B. coefficients C. products D. catalysts

C. products

A chemical reaction in which an uncombined element replaces an element that is part of a compound is called a ___ reaction. A. synthesis B. decomposition C. single replacement D. double replacement

C. single replacement

H2 + Cl2 -> HCl A. single replacement B. double replacement C. synthesis D. decomposition

C. synthesis

The ___ reaction is the opposite of the decomposition reaction. A. single replacement B. double replacement C. synthesis D. decomposition E. combustion

C. synthesis

Which is the correct product for the following double-replacement reaction? 2Kl + Pb(NO3)2 -> 2KNO3 + ? Pb (+2) I (-1) O (-2) A. PbO B. PbO2 C. PbI D. PbI2

D. PbI2

Which of the following will not increase the rate of a chemical reaction? A. an increase in concentration B. an increase in temperature C. the presence of a catalyst D. a decrease in surface area

D. a decrease in surface area

In the cannon demo that shot out the yellow Nerf ball, ___ was placed in the PVC pipe that exploded with a spark. A. gasoline B. propane C. natural gas D. alcohol E. methane

D. alcohol

When a chemical reaction occurs, there is always a change in? A. Energy and mass B. the properties and masses of the reacting substances C. the kids of atoms involved D. both the energy and properties of the reacting substance

D. both the energy and properties of the reacting substance

HgO -> Hg + O2 A. single replacement B. double replacement C. synthesis D. decomposition

D. decomposition

In a ___ reaction, one compound is broken down into 2 or more simpler substances. A. single replacement B. double replacement C. synthesis D. decomposition E. combustion

D. decomposition

The chemical equation Al2(SO4)3 + 3BaCl2 ---> 2AlCl3 + 3BaSO4 represents the ___ reaction. A. synthesis B. decomposition C. single replacement D. double replacement

D. double replacement

Any substance that enters into a chemical reaction is called a A. catalyst B. product C. coefficient D. reactant

D. reactant

A catalyst is a... A. reactant that speeds up the rate of a reaction B. product that speeds up the rate of a reaction C. substance that is changed as a result of a chemical reaction D. substances that lowers the activation energy needed for a reaction

D. substance that lowers the activation energy needed for a reaction

A reactant is formed as a result of a chemical reaction.

False

Subscripts may be changed in order to balance a chemical equation.

False

To balance a chemical equation, _subscripts_ may be changed.

False: coefficients

A _decrease_ in the concentration of reactants will increase the rate of a chemical reaction.

False: increase

_Reactants_ are written to the right of the arrow in a chemical equation.

False: products

A substance that increases a reaction rate without itself being changed by the reaction is called a _catalyst_.

True

Both exothermic and endothermic reactions require activation energy.

True

Catalysts are unchanged after being involved in a chemical reaction.

True

In a _synthesis reaction_, two or more simple substances combine to form a new, more complex substance.

True

The rusting of iron is an example of a chemical reaction.

True

CCl4 + O2 -> CO2 + Cl2

combustion

ZnCl2 -> Cl2 + Zn

decomposition

A decrease in the surface are of reactants will cause a ___ in the rate of a chemical reaction.

decrease

Al2(SO4)3 + CaCl2 -> AlCl3 + CaSO4

double replacement

Na + HCl -> NaCl + H2

single replacement

Al + Br2 -> AlBr3

synthesis