Question

a conical foask contain 68.4 g of octane (C8H18). How many molecules of octane are there in flask ( atomic mass C=12 H 1u)​

Answer 1

Answer:

$mass \: of \: C_8H_{18} = 68.4 \: g \\ molar \: mass \: of \: C_8H_{18} \\ = 8 \times 12 + 1 \times 18 \\ = 96 + 18 = 114 \: g \: {mol}^{ - 1} \\ \frac{m}{M} = \frac{N}{N_A} \\ N = \frac{m \times N_A}{M} \\ = \frac{68.4 \times 6.022 \times {10}^{23} }{114} \\ = 36.132 \times {10}^{22} \\ = 3.613 \times {10}^{23} molecules \: of \: C_8H_{18} \\ \\\red{\mathfrak{ \large{\underline{{Hope \: It \: Helps \: You}}}}} \\ \blue{\mathfrak{ \large{\underline{{Mark \: Me \: Brainliest}}}}}$