Alcohol of mass 21g and density 0.7g cm-3 is mixed with 10g of water. Determine the density of the mixture [density of water = 1.0gcm-3]
-
A.
0.775gcm-3 -
B.
0.875gcm-3 -
C.
0.780gcm-3 -
D.
0.880gcm-3
Correct Answer: Option A
Explanation
(V_A = frac{M}{D} = frac{21}{0.7} = 30cm^3)
(V_w = frac{M}{D} = frac{10}{1} = 10cm^3)
Vmixture = 30 + 10 = 40cm3
Mmixture = 21 + 10 = 31g
Dmixture = (frac{m}{v} = frac{31}{40} = 0.775)