Question

1.   The mass of a liquid is 200 cg and its volume is 50 cm3. Report its density in g/mL.

2.   The specific heat of copper is 0.093 cal/g °C and the specific heat of silver is 0.057 cal/g °C. If 200 cal of heat is added to 1g of each, which of them will have a higher temperature?
3.   Calculate the heat energy evolved when 5.46 g of water rises in temperature from 25 °C to 74 °C. (the specific heat capacity of water is 4.18 J/g °C)
4.   A 0.9% NaCl solution and a 5% glucose solution are isotonic to the cells of the body. State any changes that would occur, if a red blood cell was place in a 7% NaCl solution and explain why.
5.   What is the relationship between the concentration of a base and its alkalinity/basicity?
6.   Calculate the pH of a solution that has a pOH of 12. What is the [H+]?
7.   Calculate the [H+] of a solution with a pH of 4.7. Is this substance acidic or basic?
8.   What is the pH of a solution with [OH-] of 2.35 × 10-5?
9.   What is the pH of a solution with [H+] = 3.62 × 10-4?
10.   pH + pOH =

Answer 1

1. Density =mass/Volume= 200*10^-2 gm/ 50cc =0.04 g/ml

2. Heat added increases the temperatue. Hear added= mass* specific heat* temperature difference

temperature difference= heat added/ ( mass* specific heat)

since heat added ans mass remain the same, which one is having lower specific heat gives higher temperature. specific heat of silver is less than copper, the temperature rise will be more in silver.

3. heat energy= mass* specific heat* temperature difference= 5.46*4.18*(74-25) =1118.137 Joules

5. 7% NaCl solution would be hypertonic (more concentrated) and water would flow out of the cell, causing it to shrivel (or crenate).

6. pOH =12, pH+POH =12, pH= 14-12= 2

7 . pH= 4.7, [H+] =10(-4.7)=1.995*10^-5

8. [OH-] -2.35*10^-5

pOH= -log[OH-] = 4.63,

pH= 14-4.63=9.37

9. [H+] =3.62*10-4, pH= 3.44

10. pH+POH= 14