chemistry

homewok.docx

1. 0.37/100 * 200

= 0.74 grams

2. 2.5/100 * 450

= 11.25 grams of solute

= (450 – 11.25) = 438.75 grams of solvent

3. 1.44/100 * 157

= 2.26 grams of AgNO3

4. 0.25/100 * 1kg

= 0.0025 kg of sugar.

5. Mass of aspirin in grams = 16.2/1000 = 0.00162g

= 0.00162/1.00162 * 100%

= 0.1617% mass of aspirin

6. = 11.28/261.28 * 100%

= 4.217%

7. Mass of NaCl = 12.3/100 * 55.5 = 6.8265g

Number of moles = 6.8265 / (23 + 35)

= 0.1177 moles.

8. Mass of ethanol = 10/100 * 250 = 25g

Moles of ethanol = 25/46.068

= 0.543 moles.

9. Mass of ethanol = 0.789 * 100 = 78.9 g

Total mass = 78.9 + 0.029 = 78.929g

% mass of iodine = 0.029/78.929 * 100%

= 0.0367% I2

10. Mass of vodka in 750 mL = 0.909 * 750 = 681.75g.

% mass alcohol = 272.7/681.75 * 100%

= 40% Alcohol.