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trying to get this tow qustions Q:1 the power ratings of microwave ovens are lis

ID: 491191 • Letter: T

Question

trying to get this tow qustions

Q:1

the power ratings of microwave ovens are listed in watts (1 watt = 1 J/s). How many seconds will it take a microwave oven rated at 1000 watts to warm 862 mL of soup from 33°C to 70.°C? Assume that the heat capacity and the density of the soup are the same as that of pure water.

Q2:

When 10.00 mL of a solution of strong acid is mixed with 100.00 mL of a solution of weak base in a coffee-cup calorimeter, the temperature rises from 21.4 oC to 26.3 oC. Determine q for the acid-base reaction, assuming that the liquids have densities of 1.00 g/mL and the same heat capacities as pure water.

Explanation / Answer

Q1)

mass of water = 862 mL x 1 g/ml

                      = 862 g

specific heat of soup = 4.184 J/g C

temperature rise = 70.°C - 33°C = 37 oC

Q = m Cp dT

   = 862 x 4.184 x 37

   = 133444.5 J

power rating of microwave oven = 1000 watts

1sec -------------> 1000 J

?? ----------------> 133444.5 J

time taken = 133.4 sec