A Quick Chemistry Quiz!

1. Which one of the following is the method used to separate NH4Cl from mixture containing (NH4Cl,,SiO2,,NaCl)?

Filteration

Extraction

Heat (sublimation)

1+2

2. Collegative properities of solution include all of the following except :

Boiling point elevation

Vapor pressure lowering

Equilibrium constant depression

Freezing point depression

3. Baking soda contain :

HCl

NaOH/Al

NH4+

NaHCO3

4. Which one of the following precaution is NOT true ?

Wear a lab coat

Always pour water into acid , not acid into water

Clean up all broken glass ware immeditly

Dont perform any unauthorized expirement

5. The freezing point of a solution made by dissolved 14 g unkown in 200 g of water (k_f= 1.86 c⁰/m, T_f = 0 c⁰) decreased by 3 c⁰ ... the molar mass of unkown is :

26 g/mol

32.6 g/mol

43.4 g/mol

62 g/ mol

6. Which of the following arrangement is true according to decreasing in melting point

NaCl>NH4Cl>SiO2

SiO2>NaCl>NH4Cl

SiO2>NH4Cl>NaCl

NH4Cl>SiO2>NaCl

7. Mixture containing (NaCl,SiO₂,NH₄Cl,), NaCl = 35% , when the mixture heated it mass decreased to (0.97 g ) the remaining was dissolved in water ,the solid was filtered and its mass was (0.27 g), what is the mass of NH₄Cl in water ?

0.85 g

2.53 g

1.3 g

1.45 g

8. A mixture weighing (3.9 g) contains BaCL3.2H2o ( 244.2 g/mol ) and Na3Po4.12H2o (380.2 g/ mol ), when this mixture dissolved in water and heated for a time (0.45 g) of BaCl3.(PO4)2 is ( 602.2 g/ mol ) producrd , if BaCl3.2H2O is the limiting reactant , how many grams of Na3PO4.12H2O unreacted in the mixture ?

2.5 g

3.1 g

1.98 g

2.79 g

9. The correct measured volume in graduted cylinder with a precision of (+^_ 0.05 Cm³) is

7 Cm3

7.06 Cm3

2.3 Cm3

1.0003 Cm3