Question

calculate the (a)mass of 0.6 mole of methane (b)volume of 0.5 mole of ammonia at STP (c) number of molecules are present in 1 kg of water.​

Answer 1

Explanation:

a) Mass of 0.6 moles of Methane (CH4)

Molar mass of (M) = 16 g

$moles \: = \frac{given \: mass}{molar \: mass}$

$given \: mass \: = moles \: \times \: molar \: mass$

$given \: mass \: = 0.6 \times 16$

$given \: mass \: = 9.6 \: g$

b) Volume of 0.5 moles of ammonia

$moles \: = \frac{given \: volume}{22 .4(l)}$

$given \: volume \: = moles \times 22.4$

$given \: volume \: = 0.5\times 22.4$

$given \: volume \: =11.2 \: litres$

c) Number of molecules in 1 kg (1000 g) waters

Molar mass of water = 18 grams

Moles present in 1 kg water = 55.5

$moles \: = \frac{no .\: of \: molecules}{6.022 \times {10}^{23} }$

$no. \: of \: molecules \: = moles \: \times 6.022 \times {10}^{23}$

$= 55.5 \times 6.022 \times {10}^{23}$

$= 3.44 \times {10}^{25}$