Unit 1: Matter and Change

Question 1

What is pure substances?

Answer 1

a sample of matter with definite or constant composition (cannot change).

Question 2

What are Compounds?

Answer 2

• 2 or more elements

- can be broken down into simpler substances( by chemical reaction)

Question 3

What are Elements?

Answer 3

• smallest substances

- cannot be broken down any futher

Question 4

What is a Mixture?

Answer 4

a physical blend or 2 or more pure substances (can be separated physically)

Question 5

What are Homogeneous Mixtures?

Answer 5

• “uniform throughout”
• in a single state of matter
  ex: salt water, air,vinegar ( water & acid )

Question 6

What is an Heterogeneous mixture?

Answer 6

• “not uniform throughout”
• can be in 2 or more states of matter
  ex: oil, vinegar, blood, milk

Question 7

What is the difference between pure substances and mixtures?

Answer 7

pure substance is matter which cannot be separated into any other kind of matter when using the physical or chemical process. Mixture is a combination of two or more substances which are not united using a chemical procedure

Question 8

What is the difference between compounds and elements?

Answer 8

An element is made up of only one type of matter, divisible to a single atom with a unique number of protons, neutrons and electrons. A compound is made up of 2 or more elements

Question 9

What is matter?

Answer 9

anything that has mass or takes up space.

Question 10

What is the difference between homogenous and heterogeneous mixtures?

Answer 10

A homogeneous mixture is a substance that is uniform in composition. Solutions are examples of homogeneous mixture. A heterogeneous mixture is a mixture in which the composition is easily identified, as there are two or more phases present. Suspensions are examples of heterogeneous mixtures

Question 11

What is the difference between physical and chemical properties?

Answer 11

Physical properties are those that can be observed without changing the identity of the substance. The general properties of matter such as color, density, and hardness, are examples of these.

Chemical properties are properties that determine how a substance changes into a completely different substance. Flam

Question 12

What is a physical change?

Answer 12

A physical change changes the property of a substance without changing the substance completely. In other words, a physical change is reversible.

Question 13

Examples of physical change?

Answer 13

sublimation, decomposition, evaporation, melting, freezing, and condensation

Question 14

What is a chemical change?

Answer 14

chemical change is a change in which a substance turns into a completely different substance that can’t be reversed.

Question 15

Examples of chemical changes?

Answer 15

bike rusting, burning bread to make toast, fireworks exploding, milk spoiling, a leaf changing color, mixing eggs and flour for a batter, baking a cake

Question 16

4 clues of a chemical change?

Answer 16

• Color change
• Release of a gas
• Formation of a solid
• Production of heat and/or light

Question 17

What is the law of conservation of mass or matter?

Answer 17

1. NO mass/matter is ever cheated nor destroyed in a chemical reaction.
2. During a chemical reaction the mass of the products are always equal to the mass of the reactants.