Question

How many molecules of water are present in 3.45 mL of water at 4°C?

Answer 1

a liter of water has mass of one kg at 4 centigrade.

So we have 3.45*10^-3 kg of water
or 3.45 grams
water has mass of 16+2 = 18 grams/mole
so we have
3.45/18 = .192 moles of water
.192 * 6*10^23 = 1.15 *10^23 molecules