Question

Two hundred grams of a substance requires 18.8 kJ of heat to raise its temperature from 25°C to 45°C. Use the table to identify the substance. q = mCT. Mass (m) is in grams. Temperature is in degrees Celsius.
SUBSTANCE—C(J/g-^0C)
WATER – 2.05
IRON – 0.46
ALUMINUM – 0.90
GOLD – 0.13
COPPER – 0.39
AMMONIA (LIQUID)—4.70
ETHANOL –2.44
GASOLINE—2.22
WATER (LIQUID)—4.18
WATER (VAPOR)—2.08
Air (25^0C)—1.01
OXYGEN—0.92
HYDROGEN—14.30

water

ammonia

gasoline

air

Answer 1

@Somy

Answer 2

\[\sf Q = mc \Delta T\]
Q = is energy required to increase temp which is in this case 18.8 kJ - convert to J by multiplying to 1000
m = mass of the substance which is 200 in given q
c = specific heat capacity = unknown - you gotta find it
\[\sf \Delta T\] temperature change = final temp - initial temp (in Celsius and they are in that unit in given q)
so

\[\sf Q = mc \Delta T\]
to identify the substance you need to find c
thus make it as subject of the formula
\[\sf c =\frac{ Q }{ m \Delta T }\]
put values into the formula and get the answer

afterwards match them with given list of substances and you'll get the answer

Answer 3

sometimes your value is not exactly same as the substances given
thus the substance that has the value that is closest to the value you found - is your answer

Answer 4

I got ammonia is that what you got as well?

Answer 5

sec

Answer 6

yep
exact value :)

Answer 7

yay :D thank you! :D