Chapter 7: Chemical Reactions Review Sheet

1) In a chemical reaction

reactants

Name:

undergo a change to become

products

2) A representation of a reaction in formulas is called a

chemical

equation

3) In the law of conservation of massthe massof

reactants

must be equal to the massof

products

in a reaction.

4) To make the atoms of reactants equal to the atoms of products in an equation, you must

balance

a reaction. 5) Balance these equations: a)

4 Fe +

3 O2

b)

WO3

c)

2 PbS

d)

Na2SO4

e)

SiO2

f)

Al(OH)3

g)

2 Cr2O3

h)

CaCO3

→

2 Fe2O3

3 H2 →

+

W

3 O2 →

+

+

2

+

KCl →

+ →

3 HCl

+

→

+

single replacement

2 SO2

2 NaCl +

SiC

3 Si →

CaO

+ 3 H2O

2 PbO +

2 C →

+

synthesis

AlCl3

4 Cr +

K2SO4

double replacement

2 CO

+

3 H2O

3 SiO2

CO2 balanced

double replacement

single replacement

decomposition

6) Classify the reactions above by writing the reaction type on the line provided. (No line = no type) 7) What type of reaction only produces one product?

synthesis

8) What type of reaction has only one reactant?

decomposition

9) What type of reaction has a single element reacting with a compound and replacing an element in that compound ? single replacement

10) What type of reaction produces heat and light and frequently produces CO2and H2O as products? combustion 11) What type of reaction involves two compounds (usually dissolved in water) which switch their ion pairs?

Double replacement

12) Calculate the molar massof the following compounds: (UNITS!!!) a)

NaCl

58.44 g

b)

CaSO4

136.14g

c)

Al(OH)3

78.00 g

d)

C6H12O6 180.16g

e)

(NH4)2CO3

96.09 g

f)

FePO4

150.82g

13) Calculate the number of atoms in 4.25 moles of Na. 4.25 mol Na x 6.02 x 1023 atoms = 2.56 x 1024 atoms 1 mol 14) How many moles are in 3.45 x 1021 molecules H2O? 3.45 x 1021 molecules H2O x 1 mole = 0.00573mol H2O 23 6.02 x 10 molecules 15) How many moles do you have with 8.90 x 1023 formula units of LiCl? 8.90 x 1023 formula units LiCl x 1 mole = 1.48 mol LiCl 6.02 x 1023 f. units 16) What is the massof 9.00 moles of Li? 9.00 mol Li x

6.941 g = 62.5 g 1 mole

17) How many moles are in 15.0 g of Sulfur? 15.0 g S x

1 mole = 0.468 mol S 32.065g

18) How many atoms would you have in 1.24 grams of Carbon? 1.24 g C x 1 mole x 6.02 x 1023 atoms = 6.22 x 1022 atoms C 12.0107g 1 mol 19) What is the massof 2.66 x 1022 molecules of CO2? 2.66 x 1022 molecules CO2 x 1 mole x 44.01g 23 6.02 x 10 molecules 1 mole 20) Would the reaction of

Na + MgCl2 occur? Yes

Why or why not?

= 1.94 g CO2

Sodium is more reactive

than magnesium so it will replace the magnesium in the compound. 21) Complete the reaction of

Li + Na2SO4 → Li2SO4 + Na

22) Would the reaction of Cu + AlCl3 occur?

No

Why or why not?

The copper is not more

reactive than aluminum so it cannot replace the aluminum in the compound 23) What would be the most likely products of the reactants a) NaBa& H2SO5

b) NaSO4 & BaOH

NaOH + BaSO4

c) Na2SO4 & Ba(OH)2

24) If a reaction gives off energy to its surroundings, it is classified as

be?

d) NaOH & BaSO4

exothermic

25) If a reaction absorbs energy from its surroundings, it is classified as endothermic 26) Is this reaction endo or exothermic?

2Na + 2H2O → 2NaOH + H2 + 239.87kJ

27) If this reaction endo or exothermic? N2 + O2 + 179.91kJ → 2NO 28) Reaction rates are affected by : temperature , stirring

,

surface area

exothermic

endothermic

concentration ,

& catalysts

29) What substance can increasethe rate of a reaction but is not changed chemically in the processand can be used repeatedly?

catalysts

30) Collisions of particles can be increased by

stirring &

increasing temperature