Question

If a teaspoon of water weighs 5 grams and a single molecule of water weighs 2.98×10^−23 grams, how many molecules of water are there in a single teaspoon?

Answer 1

To find the number of water molecules in a teaspoon, calculate the number of moles from the teaspoon's weight in grams and the molar mass of water, then multiply by Avogadro's Number. Approximately 1.67 x 10^23 water molecules are present in a teaspoon of water that weighs 5 grams.

Step-by-step explanation:

To calculate the number of water molecules in a single teaspoon, we must first understand the concept of the mole, which is used in chemistry to represent 6.022 x 1023 (Avogadro's Number) of something, such as atoms or molecules. If a teaspoon of water weighs 5 grams, and the molar mass of water (H2O) is 18.015 g/mol, we can determine the number of moles of water in a teaspoon:

5 g / 18.015 g/mol = 0.2776 moles of water

Next, we multiply this by Avogadro's Number to get the number of molecules:

0.2776 moles x 6.022 x 1023 molecules/mol = approximately 1.67 x 1023 molecules

So, to answer the question, there are approximately 1.67 x 1023 water molecules in a teaspoon weighing 5 grams.