Chem
1
1
Which of the following is an example of a physical change?
a) Burning paper
b) Melting ice
c) Rusting iron
d) Cooking an egg
B. Melting Ice
Which scientist discovered the electron and proposed the “Plum Pudding” model?
a) John Dalton
b) Ernest Rutherford
c) J.J. Thomson
d) Niels Bohr
c. J.J. Thomson
Which of the following is an acidic substance?
a) Lemon juice
b) Soap
c) Baking soda
d) Saltwater
A. Lemon Juice
Which state of matter has molecules that are closely packed and vibrate in place?
a) Solid
b) Liquid
c) Gas
d) Plasma
a. Solid
What do you call a substance made of only one kind of atom?
a) Mixture
b) Compound
c) Element
d) Solution
C. Element
It is the central part of an atom which called as?
Nucleaus
Which phase change occurs when a gas turns directly into a solid?
a) Freezing
b) Condensation
c) Deposition
d) Melting
C. Deposition
Which subatomic particles are found inside the nucleus?
a) Electrons only
b) Protons and neutrons
c) Protons and electrons
d) Neutrons and electrons
C. Protons and neutrons
Which of the following is a compound?
a) Oxygen (O₂)
b) Water (H₂O)
c) Gold (Au)
d) Carbon (C)
a) Oxygen (O₂)
What process changes a solid directly into a gas?
Sublimation
What is the pH range of acidic substances?
a) 0 - 7
b) 7 - 14
c) 7 only
d) 10 - 14
A. 0 - 7
Which method is best for separating two liquids with different boiling points?
a) Filtration
b) Evaporation
c) Distillation
d) Sublimation
C. Distillation
What type of bond is formed when two atoms share electrons?
a) Ionic bond
b) Covalent bond
c) Metallic bond
d) Hydrogen bond
B. Covalent Bond
Which pH value represents a neutral substance?
a) 0
b) 7
c) 10
d) 14
B. 7
What color does litmus paper turn when dipped in an acid?
a) Blue
b) Red
c) Green
d) Purple
B. Red
Marianne observed that plants near the window grew taller than those in the shade. She tested this by placing one group of plants in sunlight and another in the shade, then measured their growth. What is the first step she followed in the scientific investigation?
a) Conducting an experiment
b) Identifying a problem or question
c) Forming a conclusion
d) Analyzing data
B. Identifying a problem or question
What happens to water molecules when they freeze?
a) They move faster and spread apart
b) They stop moving completely
c) They move closer together and form a fixed structure
d) They break apart into hydrogen and oxygen atoms
c) They move closer together and form a fixed structure
The stronger the acid, the higher its pH value.
True or False?
False
Which type of reaction occurs when an acid and a base combine?
N _ _ _ _ _ _ ization
Neutralisation
What is the major difference between Bohr’s Model and the Quantum Mechanical Model?
a) Bohr’s Model suggests fixed orbits, while the Quantum Model suggests electron clouds
b) Bohr’s Model has no protons, while the Quantum Model does
c) The Quantum Model is based on experiments, while Bohr’s Model is not
d) Bohr’s Model includes neutrons, while the Quantum Model does not
a) Bohr’s Model suggests fixed orbits, while the Quantum Model suggests electron clouds