Unit 1- Chemistry

The table below lists four unidentified substances and shows the models that represent them. Based on the information provided, classify each substance as an element, a compound, a heterogeneous mixture, or a homogeneous mixture. Write ONE correct answer in each box.

• Homogeneous mixture, Element, Compound, Heterogeneous mixture

• Element, Compound, Homogeneous mixture, Heterogeneous mixture

• Compound, Heterogeneous mixture, Element, Homogeneous mixture

• Heterogeneous mixture, Compound, Element, Homogeneous mixture

Tags

NGSS.MS-PS1-1

Which pair of elements are nonmetals and gases at room temperature and normal atmospheric pressure?

• Aluminum, Al, and neon, Ne

• Hydrogen, H, and nickel, Ni

• Chlorine, Cl, and Oxygen, O

• Cobalt, Co, and nitrogen, N

Which experiment most likely represents a chemical reaction?

• Experiment 1

• Experiment 2

• Experiment 3

• Experiment 4

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

How many carbon atoms are represented in the chemical formula CH₃COOH?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-1

What is the mass of 2KClO₃ that is decomposed in this reaction? Chemical equation: 2KClO₃ → 2KCl + 3O₂

• 39.78 g

• 8.72 g

• 63.78 g

• 378.78 g

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which property of water allows insects to walk on water?

• Surface tension

• Adhesion

• Capillary action

• Specific heat

Which chemical equation contains the fewest oxygen atoms?

• 2Na + 2H₂O → 2NaOH + H₂

• H₂O + O₂ → CO₂ + H₂

• 2AgNO₃ + K₂SO₄ → Ag₂SO₄ + 2KNO₃

• NH₄Cl + KOH → NH₃ + H₂O + KCl

A teacher conducts a demonstration to show physical and chemical changes. Which of these actions represents a chemical change?

• Melting a crayon

• Boiling a solution

• Lighting the wick of a candle

• Crushing an aluminum can

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What happens to the total mass as the reaction takes place?

• The total mass increases.

• The total mass decreases.

• The total mass doubles.

• The total mass remains the same.

Tags

NGSS.MS-PS1-5

Which statements describe chemical changes that occur during digestion? Select TWO correct answers.

• Digestive enzymes in the stomach break down proteins into smaller particles.

• Wave-like muscle contractions in the esophagus move food into the stomach.

• Enzymes in the saliva break down food before it is swallowed.

• Teeth grind food into smaller pieces in the mouth.

• The stomach muscles contract and relax, or churn, to mix food and break it down into smaller pieces.

Tags

NGSS.MS-PS1-2