chem

Question 1

example of acid?

Answer 1

hydrochloric acid
sulfur acid
nitrate acid

Question 2

physical properties of acid

Answer 2

• sour
• corrosive
• blue litmus paper to red

Question 3

example of alkalis

Answer 3

• aqueous calcium hydroxide
• aqueous sodium hydroxide
• aqueous ammonium hydroxide

Question 4

physical properties of alkalis

Answer 4

• bitter
• soapy
• red litmus paper to blue

Question 5

example of metal?

Answer 5

• calcuim
• magnesium
• zinc

Question 6

________+________—-)______+hydrogen

Answer 6

acid+metal—-)salt+hydrogen

Question 7

what is the observation of acid+metal—-)salt+hydrogen

Answer 7

effervescence and colourless gas was obsered

Question 8

how do we test for

acid+metal—-)salt+hydrogen

Answer 8

heat up the splint,cover up the mouth of test tube.If extinguish with ‘pop’ sound,hydrogen is present.

Question 9

______+_______——–)_______+________+carbon dioxide

Answer 9

acid+carbonate——-)salt +water+carbon dioxide

Question 10

observation for

acid+carbonate——-)salt +water+carbon dioxide

Answer 10

effervescence and colourless,odourless gas was observed

Question 11

how to test for

acid+carbonate——-)salt +water+carbon dioxide

Answer 11

bublle the aqueous calcium hydroxide (limewater).If white precipitate form,carbon dioxide is present

Question 12

____+______—–)_____+water

Answer 12

acid+alkaline——)salt + water

Question 13

process of

acid+alkaline——-)salt +water

Answer 13

neutralisation

Question 14

obeservation of

acid+alkaline——-)salt +water

Answer 14

• no colourless &odourless gas was observed

- felt warm

Question 15

definition of chemical change?

Answer 15

• new substance is formed
• chemical properties are different
• difficult to reverse

Question 16

different type of chemical change:

C________

Answer 16

combusion

Question 17

definition of combusion

Answer 17

process in which a substance combines with oxygen in the presence of heat to form one or more new substance

Question 18

word equation of combusion

Answer 18

reactant + oxygen ——-) products

Question 19

second type of chemical change

T_________ D________

Answer 19

thermal decomposition

Question 20

definition of thermal decomposition

Answer 20

a process in which a substance is broken down into two or more simpler substances when heated

Question 21

word equation of thermal decomposition

Answer 21

reactant A——–) product B + product C

Question 22

what is electrolysis?

Answer 22

electricty is used to break down substances into simpler substances

Question 23

denfition of physical changes

Answer 23

• no new substances
• chemical propertiees remain unchange
• can be reversed

Question 24

example of physical changes

Answer 24

• change in state
• breaking uo of substances into smaller pieces
• expansion and contraction
• mixing salt and water

Question 25

denifition of chemical reaction

Answer 25

when a new substance is made,the process that place is called a chemical reaction

new substance involed in the chemicl reaction are caled reactant

Question 26

equation for chemical reaction

Answer 26

Reactant ——-) product
left right

new substance formed are called the product