Chemistry Semester Review

Which of these sets of labels would correctly identify the diagrams in the pictures above?

• Picture 1: animal cell Picture 2: plant cell

• Picture 1: mixture Picture 2: solution

• Picture 1: compound Picture 2: element

• Picture 1: atom Picture 2: molecule

Rust is a compound with the formula Fe₂O₃. Which elements combine to form rust?

• Iron and Water

• Iron and Atoms

• Iron and Oxygen

The compound potassium sulfate, K₂SO₄, is composed of

• 2 potassium, 1 sulfur, 4 oxygen

• 2 potassium, 4 sulfur, 4 oxygen

• two molecules of potassium and one molecule of sulfate

• one molecule of potassium and two molecules of sulfate

Tags

NGSS.MS-PS1-1

Which event is an example of a chemical change?

• fog rising off a river

• wood burning in a fireplace

• ice cream melting in the sunshine

• grinding peppercorn into pepper flakes

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

When iron combines with oxygen in a moist environment, rust forms because of a

• chemical reaction

• physical reaction

• change in density

• change in temperature

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of these is an example of water changing from water vapor to liquid?

• moisture forming on a mirror when you breathe on it

• sweat forming on your body when you exercise

• ice cubes melting when you put them in a warm liquid

• rivers drying up during a very hot summer

Tags

NGSS.MS-PS1-4

NGSS.MS-ESS2-4

The physical state of a substance depends on the arrangement of atoms or molecules within it. The diagram shows the arrangement of atoms of the same substance at two different times. At Time 1 the atoms are close together. At Time 2 the atoms are moving apart. Which statement BEST describes the change occurring from Time 1 to Time 2?

• A gas becoming a solid

• A gas becoming a liquid

• A solid becoming a liquid

• A liquid becoming a solid

Dry ice changes directly from a solid to a gas. Which term describes this type of change?

• sublimation

• evaporation

• condensation

• precipitation

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Sodium sulfate and barium chloride react with each other to form sodium chloride and barrium sulfate as shown. Which statement MOST accurately describes the mass of the reactants comparred to the mass of the products?

• The mass of the reactants is the same as the mass of the products.

• The products have a greater mass because matter was created during the reaction.

• The reactants have a greater mass because some of the mass was converted to heat.

• The reactants have a greater mass because some of the matter was destroyed by the reaction.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

When a mixture of oxygen and hydrogen is ignited in a test tube, the reaction shown occurs.

Hydrogen + Oxygen -----> Water + Energy

What happens to the total mass of the contents of the test tube?

• The total mass increases.

• The total mass decreases.

• The total mass remains the same.

• Part of the mass is changed to heat energy.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5