Grade 8 Chemistry All Class Assessment and Revision of Examination


Grade 8 Chemistry All Class Assessment and Revision of Examination 

 

1.    ----------------- on Earth Without depends on water.

A.  Car

B. Life

C. Mobile

 

2.    The formula of ------------------- is H2O.

A.   carbon monoxide

B. methane

C.         water

 

3.    The hydrogen and -------------- atoms are joined by covalent bonds in water molecule.

A. oxygen

B.  carbon

C. nitrogen 

 

4.    ------------------------ is the changing of a liquid into a gas.

A. Evaporation 

B.  Condensation

C. Precipitation

 

5.    ------------------------ is the changing of a gas into a liquid.

A.  Evaporation 

B. Condensation

C. Precipitation

 

6.    A --------------------------- is an area from which water is drained.

A.  Evaporation 

B. watershed

C. Precipitation

 

 

7.    Water freezes at 0 °C and boils at 100°C.

A. True

B.  False

8.    Water is a gas at most temperatures on Earth.

A.  True

B. False

9.    Precipitation is any form of water that falls from the atmosphere and reaches the ground, such as rain, sleet, snow, or hail.

A. True

B.  False

10.                   Precipitation that flows across the land's surface and is absorbed will flow into rivers, lakes, and streams as runoff.

A.  True

B. False

11.                   Groundwater is stored in tiny holes, or pores, in soil and rocks.

A. True

B.  False

 

 

12.                   New salts enter the sea, other salts are being deposited

        on the ------------------ floor as solids.

A.  Car

B. ocean

C. Mobile

 

13.                   Oceans also contain dissolved --------------------.

A.  oxygen

B.  carbon

C. gases

 

14.                   Salts have entered the oceans following their weathering from rocks on land.

A. True

B.  False

 

15.                   The dissolved salts are carried to the sea by rivers.

A. True

B.  False

 

16.                   The oceans play an important part in the carbon cycle as reservoirs for carbon dioxide.

A. True

B.  False

 

17.                   About two-thirds of the mass of your body is made up of -----------

A.  carbon monoxide

B.  methane

C. water

 

18.                   Iron(III) hydroxide causes vegetables to turn ------------------.

A. brown

B.  blue

C. pink  

 

19.                   Dirty water is a -------------------.

A.  Evaporation 

B. sol

C. Precipitation

 

20.                   The acidity of the water is controlled using lime-----------------.

A. slurry

B.  Condensation

C. Precipitation

 

 

21.                   Calcium hydroxide is alkaline so it raises the pH of the water.

A. True

B.  False

22.                   Water is filtered through layers of stones and gravel to make sure all solids are removed.

A.  True

B. False

23.                   Remove any excess chlorine by treating the water with sulfur dioxide.

A. True

B.  False

 

 

24.                   Chlorine is added to kill bacteria in the water.

A. True

B.  False

25.                   The chlorine is reduced to chloride ions.

A. True

B.  False

 

26.                   Calcium in the -------------------- is good for children.

A.  Car

B. water

C. Mobile

27.                   Scum forms in a reaction which wastes -----------.

A.  carbon monoxide

B.  methane

C. soap

 

28.                   Calcium (or magnesium) compounds dissolved in water make it---------.

A. hard

B.  blue

C. pink  

 

29.                   Calcium sulfate is slightly soluble in -------------------.

A. water  

B.  sol

C. alcohol

 

30.                   calcium carbonate is not soluble in -----------------.

A. water  

B.  sol

C. alcohol

 

 

 

31.                   Bits of white scum will float around in the water when you use soap.

C. True

D. False

32.                   Water is filtered through layers of stones and gravel to make sure all solids are removed.

C. True

D. False

33.                   The scale formed can even block up pipes completely.

A. True

B.  False

34.                   Rainwater is the purest water.

A.  True

B. False

35.                    A coating of scale (limescale) inside copper or lead pipes stops poisonous salts dissolving into our water.

A. True

B.  False

 

 

36.                   The calcium or magnesium in the water is present as charged particles called --------------.

A.  atom

B. ion

C. molecule 

 

37.                   Calcium ions react with ions from soap (sodium stearate) to form -------.

A.  methane

B.  soap

C. scum

 

38.                   Temporarily hard water can be softened by---------------------.

A. boiling

B.  filtering

C. Cooling   

 

39.                   When you add -------------- to hard water, the calcium ions are removed.

A.  washing soda  

B.  sol

C. alcohol

 

40.                   calcium carbonate is not soluble in -----------------.

A. water  

B.  sol

C. alcohol

 

41.                   Most modern washing powders have their own water softeners.

A. True

B.  False

42.                   The column is filled with a resin which holds plenty of carbon ions.

A.  True

B. False

43.                   A solid forms when two solutions are mixed, it is called a precipitation reaction.

A. True

B.  False

44.                   The calcium ions get stuck on the resin.

A. True

B.  False

45.                    A coating of scale (limescale) inside copper or lead pipes stops poisonous salts dissolving into our water.

A. True

B.  False

 

 

 

46.                   The --------------- of a substance tells us how many grams of it will dissolve in 100g of water at a certain temperature.

A. solubility

B.  ion

C. salts 

 

47.                   Special desalination -------------- can take most of the dissolved salts out of sea water.

A.  methane

B.  soap

C. plants

 

48.                   Water is -------------------, then cooled and condensed to separate it from dissolved solids.

A.  evaporated

B.  filtered

C. Cooled

 

49.                   the solubility of sodium chloride is 36g per ---------- of water at 25°C.

A. 100g

B.  88g

C. 78g

 

50.                   100 cm3 of ------------- has a mass of 100g.

A.  water  

B.  sol

C. alcohol

 

51.                   --------------------------- is used in Middle East countries.

A.  Evaporation 

B. Desalination

C. Precipitation

 

 

52.                   Only a certain amount of solute can dissolve in a particular volume of solvent at any given temperature.

A. True

B.  False

53.                   A saturated solution is a solution in which no more solute will dissolve at a given temperature.

A.  True

B. False

54.                   The process used in some desalination plants is based on distillation.

A. True

B.  False

55.                   The calcium ions get stuck on the resin.

A. True

B.  False

56.                   Solubility curves enable you to read the solubility at temperatures you didn't investigate.

A. True

B.  False

 

57.                   The --------------- of a substance tells us how many grams of it will dissolve in 100g of water at a certain temperature.

A. solubility

B.  ion

C. salts 

 

58.                   Special desalination -------------- can take most of the dissolved salts out of sea water.

A.  methane

B.  soap

C. plants

 

59.                   Water is -------------------, then cooled and condensed to separate it from dissolved solids.

A. evaporated

B.  filtered

C. Cooled

 

60.                   the solubility of sodium chloride is 36g per ---------- of water at 25°C.

A. 100g

B.  88g

C. 78g

 

61.                   100 cm3 of ------------- has a mass of 100g.

A. water  

B.  sol

C. alcohol

 

62.                   --------------------------- is used in Middle East countries.

A.  Evaporation 

B. Desalination

C. Precipitation

 

 

63.                   Only a certain amount of solute can dissolve in a particular volume of solvent at any given temperature.

A. True

B.  False

64.                   A saturated solution is a solution in which no more solute will dissolve at a given temperature.

A.  True

B. False

65.                   The process used in some desalination plants is based on distillation.

A. True

B.  False

66.                   The calcium ions get stuck on the resin.

A. True

B.  False

67.                   Solubility curves enable you to read the solubility at temperatures you didn't investigate.

A. True

B.  False

 

 

Class Assessment

What are metals?

A solid material which is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivity.

What are non-metals?

Element or substance that is not a metal. Mostly lacks the characteristics of a metal.

What are semi-metals?

Element whose properties are intermediate between those of metals and non-metals.

 

                          

Silicon is the most well-known semi-metal. T

Groups 1 and 2 are all metals. T

Metals have small structures. F

 

Class Assessment

1.  Blend of metals has different properties to the original metals. T

2.  Aluminium alloys are not expensive. F

3.  Titanium alloys are expensive. T

4.  The main 'shape memory metal' is called nitinol. T

5.   

 

The 'ball-and-socket' type joints in the hip and shoulder have to

work especially hard. T

 

An alloy is o mixture of metals. T





Comments

Post a Comment

Popular posts from this blog

What is Intertidal zone? Define Estuary.

Image
What is Intertidal zone? Define Estuary. I ntertidal zone : O ceans are divided into zones. The shallowest part of the ocean ecosystem is called the intertidal zone. The  intertidal zone  is the area where the ocean meets the land between high and low tides. Estuary : The boundary where freshwater feeds into salt water is called an estuary . An  estuary  is an area where a freshwater river or stream meets the ocean.
Read more

Revision work for chemistry Grade-8 2021.

Revision work for chemistry Grade-8  2021.  Chose the best. 1.     In a brewery the Fermentation is carried out          in ------------------- vats. A.    Small B.    Large C.    Medium D.    All 2.     Drugs are substances which affect          the ----------------------- in some way. A.    Plastic B.    Rocks C.    Body D.    None of them 3.     I n the 1950s a new drug called Paracetamol was           introduced. A.    Paracetamol B.    Placebo C.    Emulsion D.    Fermentation 4.     An Emulsion is an example of a ---------------- . A.    Emulsion B.    Fermentation C.    Placebo D.    Colloidal 5.     Detergents are ------------------ agents. A.   ...
Read more

Define Pedigree and Carrier.

Image
Define Pedigree and Carrier. Pedigree: A pedigree is a chart used to trace the history of traits in a family. They are used to study   heredity patterns. Parents and offspring are shown in a pedigree.   Horizontal lines connect parents, and vertical lines connect parents to offspring. Males are represented as boxes ; f e mal e s ar e shown as circles. Individuals with a dominant trait have a shaded shape . Unshaded shapes represent recessiv e individu a ls . C arrier : A carrier is any individual who has inherited the gene for a trait, but does not show that trait  physically.
Read more