Question

It has been found that 221.4J is needed to heat 30g of ethanol from 15^0 C to 18^0 C. calculate

Answer 1

(a) heat(q) = mass x specific hea capacity x ∆T 
221.4 = 30 x c x 3 
c = 221.4/90 = 2.46 Jg-1 K-1 
(b) molar heat capacity = 2.4 x 46 = 110.4Jmol-1 K-1 .

Answer 2

Answer:i) 2.4

ii). 1.4

Explanation:

i). q=C∆T.  

as C=c×m

Therefore, c=q/m∆T

c=221.4/3×30

c=2.4

ii). q=no. Of moles×c

q=(given mass/molar mass)×c

q=(30/46)×2.4

q=0.6×2.4

q=1.8(approx)