Physical And Chemical Changes Flashcards Preview

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Flashcards in Physical And Chemical Changes Deck (21):
1

What happens in a chemical change?

Chemical bonds are made or broken

2

What happens in a physical change?

Chemical bonds do not change

3

What is the transition between a solid and a liquid called?

Melting

4

What is the transition between a liquid and a gas called?

Evaporating

5

What is the transition between a liquid and a solid called?

Freezing

6

What is the transition between a gas and a liquid called?

Condensing

7

Is frying an egg a physical or chemical change?

Chemical

8

Is a bike rusting a physical or chemical change?

Chemical

9

Is food dye changing the colour of water a physical or chemical change?

Physical

10

Is digestion in the stomach by stomach liquids a physical or chemical change?

Chemical

11

Is melting ice cream a physical or chemical change?

Physical

12

Is fruit ripening a physical or chemical change?

Chemical

13

Is burning a match a physical or chemical change?

Chemical

14

Is fireworks exploding a physical or chemical change?

Chemical

15

Is dissolving sugar in water a physical or chemical change?

Physical

16

Are chemical changes usually reversible?

No

17

Is a glass bottle smashing a physical or chemical change?

Physical

18

Fill in the blanks: A __________ is a long molecule made up of many smaller identical molecules (called monomers) bonded together.

Polymer

19

Fill in the blanks: Corrosion is a type of chemical reaction between a __________ and substances in its environment that results in the metal being ‘eaten away’. The most common form of corrosion that we encounter is the corrosion of iron, a process referred to as rusting. Over time, rusting can cause enormous damage to buildings, bridges, ships, railway tracks and cars.

When iron reacts with __________ and oxygen in the air it forms iron __________ and other iron compounds that make up the familiar red-brown substance known as rust.

Some substances in the environment make the rusting reaction happen much more quickly. One of the most effective of these is __________. Steel dinghies that are used in the ocean rust much faster than those that are used only in fresh water.

Metal
Water
Oxide
Salt

20

Fill in the blanks: There are a number of factors that can be changed in order to alter the speed of a chemical reaction.

The following descriptions show how we can speed up a reaction:

The __________ is increased (this means the reactant particles will be moving around faster)

The __________ of a reactant is increased (this means that there will be more particles to react)

The __________ area is increased (this means a greater number of reactant particles are exposed)

A __________ is used (although this is not used up in the reaction it causes it to happen faster)

Temperature
Concentration
Surface
Catalyst

21

Which of the following observations are good indicators that a chemical reaction may have occured?

A new substance is formed

The temperature of the substances changes spontaneously

A colour change occurs

Bubbles appear

A flame appears or light is produced

A precipitate forms

Substances mix together

A substance melts

A larger substance breaks down in to smaller ones

A new substance is formed

The temperature of the substances changes spontaneously

A colour change occurs

Bubbles appear

A flame appears or light is produced

A precipitate forms