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Worksheets8th Grade Unit 4
Total questions: 84
Worksheet time: 1hrs 24mins
Increasing the surface area of the reactants will decrease the rate of the reaction.
true
false
The amount of a substance in a given volume is the concentration of the substance.
true
false
The effect of a catalyst on a reaction is to raise the activation energy.
true
false
Only some reactions require activation energy.
true
false
An inhibitor decreases the rate of a reaction.
true
false
The burning of fuels, such as coal, natural gas, or oil, involves a(n) _______ reaction.
physical
endothermic
exothermic
In an endothermic reaction, the energy of the products is _______ the energy of the reactants.
greater than
less than
equal to
Increasing the temperature of a reaction will _______ the rate of the reaction.
increase
decrease
not affect
The amount of a substance in a given volume is called
atomic weight
molecular weight
concentration
Biological catalysts in the human body are called
enzymes
inhibitors
conductors
In a balanced chemical equation,
atoms are conserved
coefficients are equal
molecules are equal
energy is conserved
When the equation Al + Br2 → AlBr3 is balanced, the coefficient for Al is
1
2
3
4
The reaction in which hydrogen and oxygen are produced by running an electric current through water is an example of
single replacement
decomposition
synthesis
double replacement
A reaction that has two compounds as reactants and two compounds as products is most likely a
synthesis
single replacement
double replacement
decomposition
A number written in front of a chemical formula is a(n)
coefficient
atomic weight
valence
The principle that states that matter is neither created nor destroyed during a chemical reaction is called the law of
chemical energy
conservation of mass/matter
thermodynamics
The production of carbon dioxide during the burning of a fuel is an example of a(n) ________________ reaction.
synthesis
physical
endothermic
In a chemical equation, the arrow is read as
equals
leads to
yields
Which of the following is true about chemical reactions?
they are accompanied by changes in energy
they form new substances with new properties
none of these
In an endothermic reaction, energy is
absorbed
released
converted to mass
synthesized
Which of the following is NOT a physical property?
melting point
state of matter
density
flammability
Substances formed as a result of a chemical reaction are called
catalysts
precipitates
products
reactants
In an exothermic reaction, products have more energy than reactants.
true
false
Water boils at 100°C. This is an example of a chemical property.
true
false
Substances that enter into a chemical reaction are called products.
true
false
The ability to react with oxygen is an example of a chemical property.
true
false
Another name for a chemical change is a chemical bond.
true
false
In a physical change, some of the physical properties of the substance may be altered and the chemical composition remains the same.
true
false
You begin pouring sodium chloride into a glass of water. For a long time, the sodium chloride just dissolves in the water, but suddenly it begins to pile up at the bottom of the glass. Which statement is true?
The sodium chloride has increased the temperature of the water
The sodium chloride has decreased the temperature of the water
The water is unsaturated
The water is saturated
Imagine you have two beakers. Both beakers are filled with the same amount of water. The water in both beakers is the same temperature as well. You add 50 g of Substance A to the first beaker, and 50 g of Substance B to the second beaker. After stirring both beakers, there is a small pile of Substance A at the bottom of the first beaker. None of Substance B is visible in the second beaker. Which of the following statements is true?
Substance A is less soluble in water than Substance B
Substance A is more soluble in water than Substance B
Substance A is not soluble in water
Substance B is not soluble in water
Which one of the following graphs best describes the solubility of potassium nitrate (KNO3)in water at different temperatures?
A
B
C
D
Which of the charts below is most likely to represent a saturated solution?
A
B
C
D
What coefficients would balance the following equation?
__Al + __O2 → __Al2O3
2Al + 3O2 → Al2O3
2Al + 3O2 → 2Al2O3
3Al + 3O2 → 2Al2O3
4Al + 3O2 → 2Al2O3
What coefficients would balance the following equation?
__C2H6 + __O2 → __CO2 + __H2O
C2H6 + 5O2 → 2CO2 + 3H2O
2C2H6 + 5O2 → 4CO2 + 6H2O
2C2H6 + 7O2 → 4CO2 + 6H2O
2C2H6 + 10O2 → 4CO2 + 6H2O
Classify the chemical reaction shown here:
Mg + H2SO4 → MgSO4 + H2
combination
single replacement
decomposition
double replacement
Classify the chemical reaction shown here:
CaCO3 → CaO + CO2
combination
single replacement
decomposition
double replacement
Which of the following is an example of a double replacement reaction?
3Fe + 2O2 → Fe3O4
BaCl2 + K2CO3 → BaCO3 + 2KCl
NiCO3 → NiO + CO2
Cl2 + 2NaBr → 2NaCl + Br2
A white powder is added to a solution. The images show observations made before the powder is added, just after the powder has been added, and a little while later. (The liquid in the small beaker is phenol red solution.) What evidence shows that a chemical change has taken place?
a gas is produced
the pH changes
the temperature changes
all of these
none of these
A chemical reaction is done in the setup shown, resulting in a change of mass. What will happen if the same reaction is done in a sealed container that is placed on the electronic balance?
The mass will decrease because matter is lost in this reaction
The mass will stay the same because the gases produced in the reaction are kept inside the container
The mass will increase because the solids react with gas to produce more solids
There is not enough information to predict whether the mass will increase, decrease, or stay the same during the reaction in a closed container
Based on its formula, what type of chemical reaction occurs between silver nitrate (AgNO3) and copper (Cu)?
2AgNO3 + Cu → 2Ag + Cu(NO3)2
synthesis
decomposition
single replacement
double replacement
You begin pouring sodium chloride into a glass of water. For a long time, the sodium chloride just dissolves in the water, but suddenly it begins to pile up at the bottom of the glass. Which statement is true?
The sodium chloride has increased the temperature of the water
The sodium chloride has decreased the temperature of the water
The water is unsaturated
The water is saturated
Imagine you have two beakers. Both beakers are filled with the same amount of water. The water in both beakers is the same temperature as well. You add 50 g of Substance A to the first beaker, and 50 g of Substance B to the second beaker. After stirring both beakers, there is a small pile of Substance A at the bottom of the first beaker. None of Substance B is visible in the second beaker. Which of the following statements is true?
Substance A is less soluble in water than Substance B
Substance A is more soluble in water than Substance B
Substance A is not soluble in water
Substance B is not soluble in water
Which one of the following graphs best describes the solubility of potassium nitrate (KNO3)in water at different temperatures?
A
B
C
D
Which of the charts below is most likely to represent a saturated solution?
A
B
C
D
Which of the following substances is NOT an acid?
HCl
H2SO4
NaOH
HNO3
The negative ion found in bases is the
hydroxide ion
hydrogen ion
carbonate ion
water ion
Which of the following substances is most likely to have a pH close to 7?
lemon
antacid
baking soda
vinegar
Which of the following statements is NOT true about neutralization?
An acid & a base are the reactants
A salt & water are the products
There is no color change in litmus paper when the reaction is over
It produces an acid-base mixture that is more acidic than both the individual starting solutions
A solution with a pH of 2 is _____ acidic than(as) a solution with a pH of 6.
equally
less
more
Chemists use the _____ to express the concentration of hydrogen ions in a solution.
pH scale
valence
atomic number
An acid produces _____ ions in water.
helium
hydrogen
oxygen
Substances with pH values close to 14 are strong _____.
acids
bases
solutions
A strip of blue litmus paper placed in a beaker of vinegar will turn _____.
red
white
black
A base produces _____ ions in water.
metal
hydroxide
salt
A solution in which more solute can be dissolved is called a(n) ______________ solution.
saturated
unsaturated
stable
A solution in which 50 grams of solute is dissolved in 250 grams of solution has a concentration of ______ %.
20
50
5
When saturated solutions are ______ they usually become unsaturated solutions.
cooled
frozen
heated
Ionic and polar compounds usually dissolve in _________ solvents
ionic
neutral
polar
The concentration of a solution can be changed by ______________ solute.
adding
removing
replacing
A solution in which only a little solute is dissolved in a certain amount of solvent is called a concentrated solution.
true
false
As the pressure of the gas over a solution decreases, the solubility of a gas solute in a liquid solvent increases.
true
false
The solubility of table sugar in water increases as the temperature increases.
true
false
The solubility of a gas dissolved in a liquid increases as the temperature of the liquid increases.
true
false
Three factors that affect the solubility of a substance are pressure, the type of solvent, and volume.
true
false
Which of the following is NOT a property of an acid?
corrosive
reacts with metals & carbonates
turns red litmus paper blue
tastes sour
Because it wears away certain materials, an acid is described as
concentrated
contaminated
corrosive
carbonated
Which of the following best describes bases?
slippery & taste sour
turn red litmus paper blue & react with metals
taste bitter & react with carbonates
turn red litmus paper blue & taste bitter
Which of the following best describes acids?
taste sour & react with metals
taste bitter & reacts with carbonates
slippery & turn blue litmus paper red
reacts with metals but not carbonates
A compound that changes color when it comes into contact with an acid or a base is a(n)?
ionic
polar
indicator
A base ____ with carbonates
sometimes reacts
always reacts
never reacts
If carbon dioxide gas is produced when dilute acid is applied to a rock's surface, the rock is most likely made of
limestone
lava
iron
Because vinegar contains a(n) ________ it tastes sour.
acid
base
emulsion
Many soaps and detergents contain
acids
bases
sulfur
The acid in the human stomach that aids in digestion is _____ acid.
acetic
sulfuric
hydrochloric
Which of the statements about the effect of solutes on solutions is true?
solutes raise the boiling point of a solvent
water with a solute dissolved in it will freeze at 0 Celsius
solutes raise the freezing point of a solvent
antifreeze boils at a lower temperature than pure water
Brass is a solution in which a solid is dissolved in a
liquid
gas
solid
water
Which of the following statements about solutions is NOT true?
solutions are mixtures
solutions contain a solvent dissolved in a solute
a solution has the same properties throughout
the solute in the solution can be a solid, liquid, or a gas
Which of the following statements about the particles in a solution is true?
When an ionic solid mixes with water, its ions repel water molecules
when a molecular solid mixes with water, the covalent bonds are broken
when an ionic solid mixes with water, water molecules surround each ion
when a molecular solid mixes with water, water molecules surround each ion
If a suspension is allowed to stand, the particles settle out.
true
false
Solutions and colloids are similar in that both are suspensions.
true
false
The largest particles in a colloid are smaller than the largest particles in a solution.
true
false
The freezing point of a solvent decreases as solute is added.
true
false
Molecular compounds in water conduct an electric current.
true
false
A characteristic property of a solution is that it can scatter light.
true
false
