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WorksheetsScientific Method & Basic Chemistry Concepts
Total questions: 139
Worksheet time: 46mins
Which statement best describes an independent variable in an experiment?
Factor the investigator changes intentionally
Outcome variable affected by the test
Data counted or measured after testing
Condition kept constant across all trials
Which is the dependent variable in an experiment measuring plant flower count under different light durations?
Plant species used in trials
Number of flowers per plant
Hours of sunlight each day
Length of the experiment period
In a controlled experiment, what happens to variables other than the independent variable?
They are ignored completely
They are changed gradually
They are measured only
They are kept constant
Which is the correct SI base unit for mass?
Gram (g)
Newton (N)
Liter (L)
Kilogram (kg)
Which metric conversion is correct: 0.14 hectograms equals how many grams?
140 grams
0.014 grams
1.4 grams
14 grams
Convert 0.003 kilograms to grams.
30 grams
3 grams
0.3 grams
3000 grams
How many grams are in 150 centigrams?
15 grams
1.5 grams
0.15 grams
0.015 grams
Convert 4526 milligrams to grams.
0.4526 grams
4.526 grams
0.04526 grams
45.26 grams
Which scenario shows a direct relationship between two variables?
As distance increases, time remains constant
As force increases, mass stays the same
As temperature increases, gas volume increases
As pressure increases, volume decreases
Which description fits an inverse relationship?
Variables move in the same direction
Variables change randomly over time
Variables move in opposite directions
Variables do not change together
Which is an example of a physical change?
Iron rusting in moist air
Water freezing into ice
Silver tarnishing on exposure
Sugar reacting with acid
Which is an example of a chemical change?
Copper burning to form oxide
Water boiling into vapor
Salt dissolving in water
Ice melting into water
Which is a physical property useful for identifying substances?
Density at room temperature
Reactivity with acids
Ability to rust outdoors
Tendency to burn readily
Which set lists three physical properties used to identify an unknown substance?
Color, odor, reactivity with acid
Solubility, taste, magnetism
Density, melting point, boiling point
Flammability, combustibility, toxicity
Which is a chemical property?
Ability to tarnish over time
Density of 1 g/mL
Melting point at 0°C
Boiling point near 100°C
How can you tell a chemical change has occurred?
A new substance with new properties forms
The shape changes without new matter
The temperature is measured precisely
The mass is conserved perfectly
What is an element?
Matter made of one kind of atom
Blend of substances not bonded
Atoms of two elements chemically joined
Liquid part of a solution
What is a compound?
Mixture with uniform composition
Material with variable composition
Substance with atoms chemically bonded
Substance of identical atoms only
What is a mixture?
Atoms chemically bonded together
Material of a single pure element
Combination of substances not bonded
Solution with one solute only
Which statement distinguishes homogeneous from heterogeneous mixtures?
Heterogeneous is uniform; homogeneous is not
Both are uniform throughout always
Homogeneous is uniform; heterogeneous is not
Neither can be separated physically
Which statement describes a solution?
Large particles visible and separable
Uniform mixture at the molecular level
Evenly dispersed tiny particles
Particles settle quickly over time
Which statement describes a colloid?
Pure substance of one element
Particles settle forming layers
Particles scatter light noticeably
Uniform molecular-level mixture
Which statement describes a suspension?
Particles are atoms chemically bonded
Large particles eventually settle
Uniform solution at molecular scale
Particles remain evenly dispersed
In a solution, what is the solvent?
Substance that dissolves the solute
Solid formed during mixing
Gas produced by reaction
Substance present in smaller amount
Which statement best defines solubility for a solute in a solvent?
The speed at which particles mix at any temperature
The maximum amount that dissolves at given conditions
The volume of solvent required to dissolve any solid
The mass of solution formed regardless of pressure
Which mixture has higher concentration?
5 g salt in 200 g water
10 g salt in 50 g water
10 g salt in 200 g water
5 g salt in 50 g water
Which change increases the rate at which a solute dissolves in a solvent?
Use larger solute chunks
Cool and leave the mixture still
Increase temperature of the solvent
Decrease surface area of solute
On a typical solubility curve, what does each point represent?
Number of particles colliding in the solution
Rate of dissolution over time and mixing
Total mass of solvent across all temperatures
Maximum grams dissolved at a specific temperature
What is matter?
Anything invisible without any particles
Anything that flows and cannot be measured
Anything that produces energy and light only
Anything that has mass and takes up space
Which description fits a solid?
No definite shape and no definite volume
Definite shape and no definite volume
No definite shape and definite volume
Definite shape and definite volume
Which description fits a liquid?
Definite shape, no definite volume
Definite shape and definite volume
Definite volume, no definite shape
No definite shape or volume
Which description fits a gas?
Definite shape, no definite volume
No definite shape, definite volume
Definite shape and definite volume
No definite shape or volume
When thermal energy is added to matter, which two changes can occur to its particles?
Lose energy or stop vibrating
Move faster or spread farther apart
Slow down or contract tightly
Change mass or become heavier
What is the scientific definition of temperature?
Measure of average kinetic energy of particles
Amount of heat a sample can absorb in total
Speed of phase change in a material over time
Number of collisions in a closed container
As the temperature of matter increases, what happens to its particles?
They gain mass and become denser
They stop moving and become rigid
They move faster with more kinetic energy
They move slower with less energy
During melting, which energy change occurs and how is it classified?
No energy change; neutral process
Energy absorbed; exothermic process
Energy released; exothermic process
Energy absorbed; endothermic process
Which pairing correctly matches the phase change with energy and classification?
Condensation: energy released; exothermic
Vaporization: energy released; exothermic
Sublimation: energy released; exothermic
Freezing: energy absorbed; endothermic
Which statement about temperature during a phase change is correct?
Temperature decreases only in endothermic changes
Temperature increases steadily without plateau
Temperature remains constant while phase changes
Temperature spikes briefly then falls sharply
Which relationship describes Boyle’s Law for a gas at constant temperature?
Volume is independent of pressure changes
Pressure is constant regardless of volume
Pressure is directly proportional to volume
Pressure is inversely proportional to volume
If the volume of a gas decreases at constant temperature, what happens to the pressure according to Boyle’s Law?
Pressure becomes zero suddenly
Pressure increases proportionally
Pressure remains unchanged
Pressure decreases linearly
Which relationship describes Charles’ Law for a gas at constant pressure?
Temperature is independent of volume changes
Volume is inversely proportional to temperature
Volume is directly proportional to temperature
Pressure is directly proportional to mass of gas
Which subatomic particle defines the atomic number of an element?
Electron count in shells
Neutron count in nucleus
Proton count in nucleus
Total particles in atom
What is an isotope best described as?
Atom with split nucleus
Atom with different neutrons
Atom with extra protons
Atom lacking electrons
Where is a proton located and what is its charge?
Shells, negative
Nucleus, positive
Nucleus, neutral
Shells, neutral
What is the charge and typical location of an electron?
Positive, in shells
Positive, in nucleus
Neutral, in nucleus
Negative, in shells
What is the mass number of an atom equal to?
Electrons plus neutrons
Electrons plus protons
Protons plus neutrons
Neutrons minus protons
What does it mean for a nucleus to be radioactive?
Unstable and decays
Stable and energy-free
Large and inert
Charged and magnetized
Over time, when radioactive elements emit particles and radiation, what happens to their stability?
Mass number increases
Charge becomes positive
Stability decreases
Stability increases
An element has 10 electrons, 13 protons, and 14 neutrons. What is its atomic number?
14
13
10
27
An element has 10 electrons, 13 protons, and 14 neutrons. What is its mass number?
10
13
27
24
An element has 10 electrons, 13 protons, and 14 neutrons. What is its net charge as an ion?
0
+1
−3
+3
An element has 8 electrons, 8 protons, and 10 neutrons. What is its atomic number?
16
18
10
8
An element has 8 electrons, 8 protons, and 10 neutrons. What is its mass number?
18
16
8
10
Carbon-14: Which statement is correct?
Mass number equals 6
Atomic number equals 14
Electrons equal 8
Atomic number equals 6
How are elements arranged on the modern periodic table?
Alphabetical by name
Decreasing reactivity
Increasing atomic number
Increasing mass number
Where are nonmetals generally located and what properties do they share?
Bottom, radioactive
Left side, malleable
Right side, poor conductors
Middle, magnetic
What do vertical columns (groups) on the periodic table indicate?
Same number of shells
Same valence electrons
Same atomic mass
Same isotopes present
Which metals are most reactive and what ion charge do they commonly form?
Transition metals, 2−
Alkali metals, 1+
Halogens, 1−
Noble metals, 0
What specific part of the atom is involved in bonding?
Core neutrons
Inner electrons
Valence electrons
All protons
Why do atoms form bonds with other atoms?
To change into isotopes
To decrease atomic number
To complete outer shell
To lose their nuclei
Metals tend to ______ their valence electrons and form __________ ions.
gain electrons, negative
gain electrons, positive
lose electrons, positive
lose electrons, negative
Nonmetals tend to ______ their valence electrons and form __________ ions.
gain electrons, negative
lose electrons, positive
lose electrons, negative
gain electrons, positive
Practice naming the ionic compound MgS.
magnesium monosulfide
magnesium sulfur
magnesium sulfate
magnesium sulfide
Practice writing the formula for aluminum oxide.
AlO
Al2O3
AlO2
Al3O2
Practice writing the formula for lithium oxide.
LiO
Li2O
LiO2
Li2O2
Practice naming the covalent compound N2O4.
dinitrogen tetroxide
nitrogen tetroxide
nitrogen dioxide
dinitrogen dioxide
Practice naming the covalent compound SO3.
sulfur monoxide
sulfur(III) oxide
sulfur trioxide
sulfur dioxide
Practice writing the formula for iodine heptafluoride.
IF6
IF7
I2F7
IF5
What happens during a chemical reaction?
atoms are created and destroyed
elements change into energy directly
atoms rearrange to form new substances
mass disappears after products form
What is the Law of Conservation of Mass?
Mass is created during reactions
Matter changes forms; mass conserved
Mass increases when energy is released
Atoms vanish in endothermic processes
What is a subscript in a chemical formula?
charge on an ion in the formula
small number indicating atom count
mass of the compound in grams
number of molecules present
What is a coefficient in a chemical equation?
small number showing atom count
large number showing molecule count
number showing ion charge
symbol indicating state of matter
In 4AlCl₃, how many chlorine atoms are present?
4
3
7
12
In 4AlCl₃, how many aluminum atoms are present?
12
1
3
4
Is AlCl₃ an ionic or covalent compound?
network
metallic
covalent
ionic
In 5CH4, how many carbon atoms are present?
5
1
20
4
In 5CH₄, how many hydrogen atoms are present?
5
4
1
20
Is CH₄ an ionic or covalent compound?
ionic
covalent
metallic
acidic
Balance: N2 + Cl2 → NCl3. Choose the correct coefficients.
1,1,1
1,3,1
1,3,2
1,3,2 for N2
In the reaction Zn + HCl → ZnCl2 + H2, what is the balanced coefficient for HCl?
3
4
2
1
Describe a synthesis reaction.
ions in two compounds swap partners
one element replaces another element
two reactants combine to one product
one reactant forms two products
Describe a decomposition reaction.
ions in compounds exchange partners
one compound breaks into parts
one element replaces another element
two reactants combine into one
What is a catalyst?
substance consumed in reaction
substance lowering activation energy
substance raising activation energy
substance stopping reaction completely
What is an inhibitor?
substance lowering product energy
substance raising reactant energy
substance slowing reaction rate
substance speeding up reaction
How can you increase the rate of a chemical reaction?
remove catalyst and reduce collisions
lower temperature and surface area
raise activation energy and dilute
increase temperature or concentration
Which statement describes an exothermic reaction?
products have more energy than reactants
reactants have more energy than products
energy is absorbed from surroundings
activation energy equals zero always
Which statement describes an endothermic reaction?
activation energy is lower with catalyst
energy released to surroundings
reactants have more energy than products
reactants have less energy than products
In a controlled experiment, what must be true about all variables except the independent variable?
They are eliminated from the setup entirely
They are measured but never recorded
They are kept constant across all trials
They are changed randomly during trials
What is the base SI unit for mass?
Kilogram (kilogram)
Ounce (ounce)
Pound (pound)
Gram (gram)
What is the base SI unit for length?
Foot (foot)
Meter (meter)
Yard (yard)
Kilometer (kilometer)
What is the base SI unit for temperature?
Celsius (celsius)
Kelvin (kelvin)
Fahrenheit (fahrenheit)
Degree (degree)
Use metric conversions to determine the amount of grams in 0.14 hectograms.
1.4 grams
14 grams
140 grams
0.014 grams
Use metric conversions to determine the amount of grams in 0.003 kilograms.
300 grams
30 grams
3 grams
0.3 grams
Use metric conversions to determine the amount of grams in 4526 milligrams.
4.526 grams
45.26 grams
0.4526 grams
452.6 grams
Which example best illustrates a direct relationship?
As temperature falls, pressure rises
As temperature changes, pressure stays constant
As temperature rises, pressure decreases
As temperature rises, pressure rises
What is an inverse relationship between two variables?
One variable increases while the other decreases
Variables move in the same direction
Both variables remain unchanged
Both variables decrease together
Which set lists three examples of physical changes?
Rusting, burning, rotting
Cutting, heating, dissolving
Tarnishing, fermenting, cooking
Neutralizing, oxidizing, reacting
Which pair lists two examples of chemical changes?
Melting and freezing
Cutting and condensing
Dissolving and reshaping
Burning and rusting
Which group lists three physical properties used to identify an unknown substance?
Flammability, reactivity, combustibility
pH, conductivity, radioactivity
Density, melting point, boiling point
Hardness, malleability, ductility
Which pair lists two examples of chemical properties?
Density and color
Flammability and reactivity
Boiling point and melting point
Mass and volume
What is a compound?
A physical blend of metals only
Matter made of a single atom type
Two or more substances not chemically combined
Two or more elements chemically combined
Which statement correctly compares homogeneous and heterogeneous mixtures?
Heterogeneous have small particles; homogeneous large
Homogeneous always scatter light; heterogeneous never
Heterogeneous cannot be separated; homogeneous can
Homogeneous have uniform composition; heterogeneous do not
Which mixture type has small solute particles, cannot be filtered, and does not scatter light?
Emulsion
Solution
Suspension
Colloid
Which mixture type has large solute particles, can be filtered, and scatters light?
Solution
Alloy
Suspension
Colloid
Which mixture type has medium solute particles, cannot be filtered, and scatters light?
Solution
Suspension
Colloid
Solvent
Which statement best defines a solvent in a solution?
The gas produced during dissolution
The solid formed after a solution cools
The substance that is dissolved by another substance
The substance that dissolves the other substance
Which example correctly identifies the solute in salt water?
Salt and water are both solutes
Neither salt nor water is a solute
Salt is the solute dissolved in water
Water is the solute dissolved in salt
What does solubility describe?
The speed a solute dissolves in a solvent
The amount of solute that can dissolve at given conditions
The temperature required to melt a solid
The mass of solvent used in a mixture
Which action lowers the concentration of a very sweet sugar solution?
Add more sugar to the solution
Add more water to the solution
Heat the solution to a higher temperature
Stir the solution more quickly
Which change most often increases the rate at which a solute dissolves in a solvent?
Decreasing temperature and stirring less
Crushing the solute and stirring more
Using a larger beaker without stirring
Adding ice and leaving the mixture still
Which statement correctly defines matter?
Anything that forms a solution
Anything that can conduct electricity
Anything visible to the human eye
Anything that occupies space and has mass
Which description matches the particles in a solid?
Particles spread apart with no definite volume
Particles vibrate in fixed positions, definite shape
Particles compress easily under low pressure
Particles move freely and fill any container
What two changes occur to particles when thermal energy is added?
Lose mass, change identity
Increase kinetic energy, speed up
Decrease kinetic energy, slow down
Gain protons, become ions
What is the scientific definition of temperature?
The average kinetic energy of particles
The force exerted per unit area
The total heat a substance contains
The amount of solute in a solvent
During a phase change such as melting or boiling, what happens to temperature?
It increases steadily with time
It decreases quickly to zero
It does not change while the phase changes
It fluctuates randomly
Which process is endothermic and absorbs energy from surroundings?
Condensation releases energy to surroundings
Deposition absorbs energy from surroundings
Freezing releases energy to surroundings
Vaporization absorbs energy from surroundings
Which statement best describes Boyle’s Law?
Pressure is directly proportional to volume at constant temperature
Volume is directly proportional to moles at constant pressure
Pressure is inversely proportional to volume at constant temperature
Volume is inversely proportional to temperature at constant pressure
Which statement best describes Charles’ Law?
Pressure is directly proportional to temperature at constant volume
Volume is inversely proportional to temperature at constant pressure
Pressure is inversely proportional to volume at constant temperature
Volume is directly proportional to temperature at constant pressure
Which definition correctly describes pressure in a gas?
Heat per unit time transferred
Energy stored per mole of gas
Mass per unit volume of the gas
Force per unit area from particle collisions
Which change would increase the dissolution rate of table salt in water the most?
Grinding salt and using warmer water
Reducing surface area by making larger crystals
Lowering temperature and leaving it unstirred
Adding more water but keeping it cold
Which statement compares high and low solubility of a solute correctly?
High solubility means less dissolves at given conditions
Low solubility means more dissolves at given conditions
High solubility means more dissolves at given conditions
Solubility is unrelated to amount dissolved
An atom has 10 electrons, 13 protons, and 14 neutrons. What is its net charge?
0 overall charge
−3 overall charge
+3 overall charge
+1 overall charge
An atom has 10 electrons, 13 protons, and 14 neutrons. What is its mass number?
23
29
24
27
An atom has 8 electrons, 8 protons, and 10 neutrons. What is its atomic number?
6
7
8
10
An atom has 8 electrons, 8 protons, and 10 neutrons. What is its mass number?
16
20
17
18
Uranium‑239 has atomic number 92. How many neutrons does it contain?
92
331
147
239
How are elements arranged on the modern periodic table?
By increasing reactivity
By increasing atomic number
By increasing number of neutrons
By increasing atomic mass
Where are metals mostly located on the periodic table, and what is a shared property?
Center, colorless gases
Left side, good conductors
Top rows, poor conductors
Right side, brittle solids
Where are metalloids found, and what is a shared property?
Along the staircase, semiconductors
Far right column, gas at room temp
Top rows, dense metals
Bottom two rows, radioactive
What are the horizontal rows on the periodic table called, and what do they indicate?
Blocks, metallic character
Periods, energy shells count
Groups, valence electron count
Families, neutron number
Which nonmetals are most reactive and what charge do their ions typically have?
Halogens, −1 charge
Chalcogens, +2 charge
Metalloids, +1 charge
Noble gases, 0 charge
Which part of the atom is directly involved in chemical bonding?
Valence electrons
Protons in the nucleus
Entire electron cloud
Neutrons in the nucleus
How many electrons can occupy the first energy shell of an atom?
8 electrons
18 electrons
1 electron
2 electrons
Which type of bond forms between a metal and a nonmetal?
Hydrogen bond
Metallic bond
Covalent bond
Ionic bond
Balance the equation: N2 + Cl2 → NCl3. What are the lowest whole-number coefficients?
1 N2 + 1 Cl2 → 2 NCl3
1 N2 + 2 Cl2 → 2 NCl3
1 N2 + 3 Cl2 → 2 NCl3
2 N2 + 3 Cl2 → 4 NCl3
Zinc reacts with hydrochloric acid: Zn + HCl → ZnCl2 + H2. Which balanced coefficients satisfy the law of conservation of mass?
1 Zn + 2 HCl → 2 ZnCl2 + 1 H2
1 Zn + 2 HCl → 1 ZnCl2 + 1 H2
1 Zn + 1 HCl → 1 ZnCl2 + 1 H2
2 Zn + 2 HCl → 2 ZnCl2 + 2 H2
Which description best matches a synthesis reaction?
One reactant breaks into several products
Ions from two compounds exchange partners
A more reactive element replaces a less reactive one
Two or more substances combine to form one product
Which change would most likely increase the rate of a reaction between a solid and a solution?
Use an inhibitor substance
Lower the temperature of the system
Dilute the reactants to lower concentration
Grind the solid to increase surface area
What is the role of a catalyst in a chemical reaction?
Stops reaction by consuming reactants
Changes products by altering stoichiometry
Speeds reaction by lowering activation energy
Slows reaction by raising activation energy
