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Science Year 8 > Reactions > Flashcards

Reactions Flashcards

1
Q

What are the two types of changes in reactions?

A

Chemical and physical changes

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2
Q

What are some factors of physical changes?

A
  • no new compounds formed
  • melting, boiling, freezing, condensing etc.
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3
Q

What are some factors of chemical changes?

A
  • new compound formed
  • Signs:
  • temp change
  • bubbles
  • colour change
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4
Q

What is another word for bubbles?

A

Effervesces

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5
Q

What are the three types of variable?

A

Independent
Dependant
Controll

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6
Q

Which variable is the one that changes

A

Independent variable

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7
Q

What does the dependant variable do?

A

Feature that is measured

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8
Q

What does the control variable do?

A

A feature that is kept constant

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9
Q

Name two examples of reaction

A
  • oxidation
  • thermal decomposition
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10
Q

What happens to mass in chemical reactions?

A

It is never lost or gained (law of conservation of mass)

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11
Q

Define exothermic reaction

A

Gives out thermal energy to the environment

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12
Q

Does the temperature rise or fall in an exothermic reaction?

A

It rises and gets hot

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13
Q

Give two examples of exothermic reactions

A

Combustion and most catalysts

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14
Q

Define endothermic reaction

A

Takes in thermal energy from the environment

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15
Q

Which type of reaction ( endothermic or exothermic ) does the temp fall?

A

Endothermic

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16
Q

Name two examples of endothermic reactions

A

Thermal decomposition and ammonium nitrate

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17
Q

What are catalysts and what do they do?

A

Speeds up a reaction without being used up and provides an alternate easier pathway for reactions to occur (lowers energy for the reaction to occur)

18
Q

What are the two types of catalysts?

A

Industrial catalysts (usually contain transitional metals)
Biological catalysts (enzymes)

19
Q

Give two examples of industrial catalysts

A
  • platinum speeds up combustion
  • iron used in the Haber process
20
Q

Give two examples of biological catalysts

A
  • catalase (lipase) found in the liver
  • amylase found in saliva
21
Q

Define combustion

A

When a fuel reacts with oxygen (exothermic reaction)

22
Q

What are some features of complete combustion? (

A
  • ample oxygen present
  • products = water and co2 (greenhouse gas)
23
Q

What are some factors of incomplete combustion?

A
  • little oxygen present
  • products= water,Co (toxic gas), soot (can irritate the lungs if inhaled)
24
Q

Give the equation for complete combustion

A

Fuel + oxygen ~> carbon dioxide + water

25
Q

Give the equation for incomplete combustion

A

Fuel + oxygen ~> carbon monoxide OR Carbon + water

26
Q

What is thermal decomposition?

A

The breakdown of a compound into similar substances due to heat

27
Q

What are carbonates?

A

Compounds that contain carbon and oxygen

28
Q

What atoms do carbonates usually consist of?

A

A metal, a carbon atom and three oxygen atoms (e.g CaCo3 calcium carbonate)

29
Q

What do metal carbonates breakdown into?

A

Metal oxide and carbon dioxide

30
Q

How do we test for carbon dioxide?

A

By bubbling gas through limewater if the limewater turns cloudy there is carbon dioxide present

31
Q

What is the equation for thermal decomposition

A

Metal carbonate ~> metal oxide + carbon dioxide

32
Q

What is another word for the clamp stand?

A

A retort stand

33
Q

What type of tube should the horizontal test tube be?

A

A boiling tube

34
Q

What are three safety precautions with the limewater testing?

A
  • hair tied back
  • goggles
  • remove limewater before stopping heating
35
Q

What 4 things do you need to do when planning an investigation?

A
  • choose variables
  • ensure control variable remains the same
  • trial run
  • set the interval - the size of the step between max and min
36
Q

What does precision mean?

A

When the results are all really close together

37
Q

What is an anomalous result?

A

When there is a result that is very different from the rest

38
Q

What does it mean is something is bias?

A

When an experimenter has a theory that they believe is true and frames data so that their conclusion agrees with the theory

39
Q

What’s an example of a bias experiment?

A

Tobacco companies setting experiments that minimise the signs of negative effects of smoking

40
Q

What are the signs of each state?

A

Solid - S
Liquid - L
Gas - g
Aqueous - aq

Science Year 8 (7 decks)

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