. A 20.0 % by mass solution of phosphoric acid (H3PO4) in water has a density of 1.114 g/mL at 20°C. What is the molarity of this solution? The molar mass of phosphoric acid (H3PO4) is 97.99 g.

2.273M

Explanation:

What is the definition of molarity.

M = mols/L. So that's what we need to determine.

How much does a L weigh? That's

1.114 g/mL x 1000 mL = 1114 grams. Simple enough, eh?

How much of that 1114 g is H3PO4. It says it is 20% by mass, therefore, 1114 g x 0.20 = 222.8 g.

How many mols are there in 222.8 g H3PO4? That's mools = grams/molar mass = 222.8/98 = 2.273 mols.

The definition of M is what? M = mols/L. And you have 2.273 mol/L; that must be the molarity.

The formula is

density g/mL x 1000 mL x mass% x (1/molar mass) = M

1.114 x 1000 x 0.20 x (1/98) = 2.273 M.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.