B.Mg(OH)2 (the active ingredient in milk of magnesia)
Hello!
To find the mass of helium, we need to multiply the total moles by the mass of helium. We are given 2.714 moles of helium, and the mass of helium is about 4.00 grams. Now, we multiply the two values together to get the grams.
2.714 moles x 4.00 grams = 10.856 grams
According to the number of significant figures, 2.714 moles of helium has a mass of 10.9 grams (exact value: 10.856 grams).
Divide the mass of the compound in grams by the molar mass you just calculated. The answer is the number of moles of that mass of compound. For example, 25 grams of water equals 25/18.016 or 1.39 moles.
All of the lower case letters are recessive
