What is the percentage of nitrogen in the atmosphere?
78%
Select the least reactive metal:A)magnesium B)sodium C)potassium D)zinc
D)zinc
Which is NOT a use of aluminium?A)food containerB)aircraft bodies C)electricity cable D)insulator
D)insulator
What is the chemical used to kill bacteria in water in the water treatment plant?
chlorine
Which reaction is used to keep the blast furnace hot?
CaCO3 → CaO + CO2
Fe2O3 + 3CO → 2Fe + 3CO2
C + O2 -> CO2
CO2 + C -> 2CO
Which metal is in liquid state at room temperature?
Mercury
Why is pure iron not used for bridges?A)too malleable B)too resistant to corrosion C)too conductive D)not shiny enough
A)too malleable
What are the products formed from the reaction between sodium and cold water?
sodium hydroxide and hydrogen
Name a chemical that can be used to test the presence of water.
anhydrous copper(II) sulfate (white to blue) OR anhydrous cobalt(II) chloride(blue to pink)
In the past, refrigerators, aerosol spray propellants and cleaning solvents were all sources of a greenhouse gas known as
CFC
What is an alloy?
A mixture of a metal with one or more other elements.
Which of the following does not prevent rusting of iron?A)painting,oiling,galvanizing B)attach to a piece of copper C)connect to a piece of magnesium with copper wire D)cover entirely with copper
B)attach to a piece of copper
State 2 harmful effects of nitrogen oxides.
acid rain, photochemical smog, respiratory problem
Covering iron with zinc is called ______________, and the zinc stops the iron from rusting.
galvanisation
Copper is sometimes used to make cooking utensils.3 of properties of copper are shown below: 1. Good conductor of electricity 2. Corrosion resistant 3. Good conductor of heat .Which of these properties make it good for cooking utensils?
2&3
magnesium + steam →
magnesium oxide + hydrogen (magnesium very slowly with cold water)
Which is NOT a use of zinc?A)sacrificial protection B)galvanising C)making bronze D)making brass
C)bronze-(copper+tin)
The ability of metal to be hammered into sheets is called ________.
malleability
Which gas contributes to acid rain?
oxides of nitrogen(e.g:nitrogen dioxide) OR sulfur dioxide
Zinc granules give hydrogen gas when treated with dilute solution of:A)FeO B)HCl C)NaCl D)Ammonia
B) HCl
Most of metals which occur in their native state in nature:A)are very active B)do not form any compound C)are not reactive D)are moderately reactive
C)are not reactive
What is the chemical name given to rust?
hydrated iron(III) oxide
In which reaction would displacement happen?A)copper + magnesium sulfate B) iron + calcium sulfate C)magnesium + copper sulfate D)iron + potassium sulfate
C)magnesium + copper sulfate
Iron is made by burning its ore, hematite. Hematite contains silica. What reacts with this impurity to remove it?
Carbon
Carbon dioxide
Silicon dioxide
Calcium Oxide
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