is matter around us pure

brass is an alloy. It is a mixture of______

• 30% Zinc 70% copper

• 20% copper 80% nickel

• 40% iron 80% copper

• 35% gold 65% zinc

colloids can be seperated by

• filtration

• distillation

• sedimentation

• centrifugation

formula to find concentration of a solution?

(a)  

how will you seperate sulphur and iron fillings

• handpicking

• sieving

• crystallization

• magnetic seperation

how will you seperate oxygen from a mixture of liquid air?

• centrifugation

• seperating funnel

• fractional distillation

• distillation

how will you seperate the components of sugar solution

• evaporation

• crystallization

• filtration

• chromatography

burning of candle is a

• physical change

• chemical change

• both physical and chemical change

• none of the above

a mixture of dye in a volatile liquid can be seperated by?

• evaporatoion

• sedimentation

• chromatography

• filtration

Tyndall effect is observed in forests because of

• tress

• high oxygen level

• mist and dust particles in the air

• less sunlight

concentration of 36g of NaCl in 100 g of water is

• 23%

• 26.47%

• 29.32%

• 21.11%