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WorksheetsChemical Reactions
Total questions: 40
Worksheet time: 35mins
Name
Class
Date
1.
Is this equation balanced?
a)
yes
b)
no
c)
Not enough information
2.
Is this equation balanced?
a)
yes
b)
no
c)
Not enough information
3.
Balance this equation
_Al +_HCl --> _H2 +_AlCl3
_Al +_HCl --> _H2 +_AlCl3
a)
2, 6, 3, 2
b)
it is already balanced
c)
4, 12, 3, 4
d)
2, 1, 4, 5
4.
Balance this equation-
__P4 + __O2 --> __P2O3
__P4 + __O2 --> __P2O3
a)
it is already balanced
b)
2, 1, 3
c)
1, 2, 3
d)
1, 3, 2
5.
Grinding a seltzer tablet into powder increases the rate of reaction due to increased
a)
concentration
b)
surface area
c)
temperature
d)
reactants
6.
Increasing the concentration increases the speed of reaction by
a)
lowering activation energy
b)
increasing collisions
c)
speeding up the reactants
d)
exposing more reactant
7.
Which factors increase the rate of a reaction.
a)
increasing temperature
b)
increasing concentration
c)
decreasing surface area
d)
increasing volume (for gases)
8.
A chemical Equation is
a)
The actual physical process of new substances forming
b)
The written story using symbols describing a reaction
c)
Neither of the above
d)
The Yield sign
9.
What is the right part of a chemical equation called?
H2 + O → H2O
H2 + O → H2O
a)
Reactants
b)
Products
c)
Yields
d)
Chemical Equation
10.
The Law of Conservation of Mass proves that -
a)
the number of atoms in a chemical reaction does not change
b)
there are more atoms on the reactant side than the product side
c)
there are more atoms on the product side than the reactant side
d)
the mass of the product will not equal the reactants
11.
In the equation,
2Mg + O2 ---> 2MgO, which are the reactants?
2Mg + O2 ---> 2MgO, which are the reactants?
a)
Mg and O2
b)
MgO
c)
Mg and MgO
d)
O2 and MgO
12.
What should be written between the reactants and products?
a)
an equal sign
b)
a triangle
c)
an arrow
d)
the word "yields"
13.
balance this skeleton equation?...
Al (s) + O2(g) --> AlO3(s)
Al (s) + O2(g) --> AlO3(s)
a)
Al + O2 --> AlO2
b)
Al + 3O2 --> 2AlO3
c)
2Al +3O2 --> 2AlO3
d)
2Al + 2O2 --> 2AlO3
14.
Balance this skeleton equation...
Sb2S3 + O2 --> Sb + SO2
Sb2S3 + O2 --> Sb + SO2
a)
It is balanced
b)
Sb2S3 + 3O2 --> 2Sb + 3SO2
c)
Sb2S3 + O2 --> 2Sb + SO2
d)
I don't know...Oh well!
15.
Balance this skeleton equation...
H2 + Cl2 --> HCl
H2 + Cl2 --> HCl
a)
It is balanced
b)
3H2 + Cl2 --> 6H2Cl
c)
H2 + Cl2 --> 2HCl
16.
What is the left part of a chemical equation called?
H2 + O → H2O
H2 + O → H2O
a)
Reactants
b)
Products
c)
Yields
d)
Chemical Equation
17.
What is the correct skeleton equation for the chemical reaction between hydrogen and oxygen to form water.
a)
H(g) + O(g) → H2O(l)
b)
2H2(g) + O2(g) → 2H2O(l)
c)
H2(g) + O2(g) → H2O2(l)
d)
H(g) + O(g) → OH(g)
18.
When the reaction that happens releases heat and therefore feels warm it is called a(n):
a)
Endothermic reaction
b)
Exothermic reaction
19.
A ______________ is a substance that increases the rate of a reaction without being used up during the reaction.
a)
catalyst
b)
product
c)
reactant
d)
solute
20.
Smaller pieces of reactants allow for a _________ surface area to be exposed for the reaction.
a)
larger
b)
smaller
21.
Increasing the concentration of the reactants will slow down the reaction.
a)
false
b)
true
22.
In an endothermic reaction the products have
a)
more energy than the reactants
b)
less energy than the reactants
c)
the same energy as the reactants
d)
no energy
23.
Why does a higher temperature increase the rate of a reaction?
a)
it increases both the frequency and energy of particle collisions
b)
it only increases the frequency of particle collisions
c)
it only increases the energy of particle collisions
d)
it reduces the activation energy of the reaction
24.
Why does a higher concentration increase the rate of reaction?
a)
it increases the amount of reactants
b)
it lowers the activation energy
c)
it increases the energy of particle collisions
d)
it increases the frequency of particle collisions
25.
Which of these will NOT speed up the rate of reaction between a strip of magnesium and hydrochloric acid?
a)
tightly coil up the strip of magnesium
b)
cut up the strip of magnesium
c)
increase the concentration of the hydrocholoric acid
d)
increase the temperature of the hydrocholoric acid
26.
Which is NOT an indication of a chemical change?
a)
temperature change
b)
formation of a precipitate
c)
shape change
d)
production of light
27.
You know you a chemical reaction has occurred if
a)
there is a precipitate.
b)
there is a color change.
c)
the reaction system gets colder.
d)
the substances remain as liquids
e)
the physical properties are still the same
28.
What do we call the numbers that are put at the front of the substances to meet the law of conservation of mass
a)
subscripts
b)
superscripts
c)
values
d)
coefficient
29.
In an exothermic reaction, heat is ...
a)
taken in
b)
given out
30.
In an endothermic reaction, heat is...
a)
taken in
b)
given out
31.
Is photosynthesis an exothermic or endothermic reaction?
H2O + CO2 + energy → C6H12O6 + O2
a)
Endothermic
b)
Exothermic
32.
When the reaction absorbs heat and feels cold, it's called a(n):
a)
Endothermic reaction
b)
Exothermic reaction
33.
You mixed a salt and an acid. The temperature of the reaction rose. This is an:
a)
Endothermic reaction
b)
Exothermic reaction
34.
What kind of reaction is this?
a)
Endothermic
b)
Exothermic
c)
Cannot be determined
35.
What are the products of the chemical reaction pictured?
a)
CH4 and CO2
b)
CH4 and O2
c)
CO2 and H2O
d)
O2 and H2O
36.
Consider the chemical equation CH4 + 2 O2 → CO2 + 2 H2O. In this equation, CH4 is a
a)
product
b)
reactant
c)
displacement
d)
catalyst
37.
Identify the reactant(s) and product(s) of the reaction.
a)
All three are reactants and none are products.
b)
Hydrogen and water are the reactants, and oxygen is the product.
c)
Water and oxygen are the reactants, and hydrogen is the product.
d)
Hydrogen and oxygen are the reactants, and water is the product.
38.
The presence of a catalyst helps speed up reactions because it helps particles collide...
a)
more frequently
b)
with the right orientation
c)
with more energy
39.
One of the signs of a chemical reaction taking place is:
a)
Bubbles of gas are produced
b)
Reactants are not combining
c)
Products are not forming
d)
Color is not changing
40.
The graph above represents the results of three experiments a reaction involving zinc and hydrochloric acid. All factors were kept constant for the three experiments except for temperature, which was intentionally changed. Based on the graph, which experiment was most likely conducted at the lowest temperature.
a)
A
b)
B
c)
C
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