Chapter 7: Chemical Reactions Review Sheet
1) In a chemical reaction
undergo a change to become
2) A representation of a reaction in formulas is called a
3) In the law of conservation of massthe massof
must be equal to the massof
in a reaction.
4) To make the atoms of reactants equal to the atoms of products in an equation, you must
a reaction. 5) Balance these equations: a)
4 Fe +
3 H2 →
3 O2 →
2 NaCl +
3 Si →
+ 3 H2O
2 PbO +
2 C →
4 Cr +
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?
8) What type of reaction has only one reactant?
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?
12) Calculate the molar massof the following compounds: (UNITS!!!) a)
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?
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
d) NaOH & BaSO4
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
29) What substance can increasethe rate of a reaction but is not changed chemically in the processand can be used repeatedly?
30) Collisions of particles can be increased by