Calculate the amount of water (in grams) that must be added to
(a) 9.00 g of urea [(NH2)2CO] in the preparation of a 8.10 percent
by mass solution: (b) 28.9 g of MgBr2 in the preparation of a 2.90
percent mass solution:
A student dissolved 10.5 g of NH4Cl in 40 mL of
water. The temperature of the water changed from
22.5oC to 5.1oC. Calculate the
enthalpy of hydration of ammonium chloride in J/mol.
1. A student collected the data below while
performing a kinetics experiment.
Trial
Volume of 2.0 M Reactant A
Volume of 0.5 M Reactant B
Volume of H2O
Time for B to react
1
10 mL
10 mL
30 mL
135 sec
2
20 mL
10 mL
20 mL
69 sec...
1.0 mol of Cu(NO3)2 is dissolved in 1000 g of water. What is the
molality of the solution for use in colligative property equations?
The answers are 1, 2, 3, 4, or cannot be determined.
Ice of mass 45.5 g at -10.5° C is added to 208 g of water at
15.8° C in a 101 g glass container of specific heat 0.200 cal/g-°C
at an initial temperature of 27.5° C. Find the final temperature of
the system.
a)Consider an aqueous solution of ammonium chloride, NH4Cl.
Neglecting the autoprotolysis of water, calculate the pH of NH4Cl
for formal concentration of 0.10M.
b)Use the systematic treatment of equilibrium to derive an
equation for an aqueous solution of NH4Cl that contains [H+], F, Ka
and Kw. Do not neglect the autoprotolysis of water in this
case.
If some NH4Cl is added to an aqueous solution of NH3:
A.
the pH of the solution will decrease
B.
the solution will not have pH
C.
NH4Cl cannot be added to NH3
D.
the pH of the solution will increase
E.
the pH of the solution will not change
A 48.78−g sample of water at 77.5°C is added to a sample of
water at 24.9°C in a constant-pressure calorimeter. If the final
temperature of the combined water is 38.1°C and the heat capacity
of the calorimeter is 26.3 J/°C, calculate the mass of the water
originally in the calorimeter.