brodidit for students
ہوم / مشق / گیارہویں جماعت / کیمیا / تجرباتی تکنیکیں
تجرباتی تکنیکیں
5 سوالات: گیارہویں جماعت کیمیا، جوابات اور وضاحت کے ساتھ۔
جوابی کنجی کے ساتھ قابلِ پرنٹ ورک شیٹ
-
Components of a mixture of liquids with different boiling points are separated by:
- 1 Sublimation
- 2 Filtration
- 3 Fractional distillation
- 4 Crystallisation
جواب دیکھیں
درست جواب: Fractional distillation
Fractional distillation separates liquids by boiling point.
-
In paper chromatography, substances separate because of differences in:
- 1 Their attraction to the paper and the solvent
- 2 Density
- 3 Colour only
- 4 Mass only
جواب دیکھیں
درست جواب: Their attraction to the paper and the solvent
Components travel at different speeds depending on their affinity to the two phases.
-
Pure solid compounds are purified from solutions by:
- 1 Distillation
- 2 Centrifuge only
- 3 Crystallisation
- 4 Evaporation to dryness only
جواب دیکھیں
درست جواب: Crystallisation
Crystallisation gives pure crystals from a saturated solution.
-
The Rf value in chromatography is the ratio of:
- 1 Solvent to substance
- 2 Distance moved by substance to distance moved by solvent
- 3 Temperature to time
- 4 Mass of substance to solvent
جواب دیکھیں
درست جواب: Distance moved by substance to distance moved by solvent
Rf = distance of spot / distance of solvent front.
-
Solvent extraction works because a solute is:
- 1 A gas
- 2 Always ionic
- 3 A catalyst
- 4 More soluble in one solvent than another
جواب دیکھیں
درست جواب: More soluble in one solvent than another
The solute moves into the solvent in which it dissolves better.