The label on a tub of margarine states that 100 g of the margarine contains 0·70 g of sodium. the sodium is present as sodium chloride. calculate the mass of sodium chloride, in grams, present in a 10 g portion of the margarine. the mass of one mole of sodium chloride, nacl, is 58·5 g.

This problem requires three conversions: 1) mass of margarine to mass of sodium, 2) mass of sodium to moles of sodium, and finally 3) moles of sodium to grams of sodium chloride (since moles of Na = moles of NaCl).

1) mass of Na = 10g marg • (0.70g Na / 100g marg)

2) moles of Na = mass of Na • (1 mol Na / 22.99g Na)

3) mass of NaCl = moles of Na • (58.5g NaCl / 1 mol NaCl)

Combining all three steps:

mass of NaCl = 10g • (0.70g / 100g) • (1 mol / 22.99g) • (58.5g / 1 mol) = 0.18g NaCl

If we check the units, we find that our final answer should be in units of grams, which it is.

Most smaller stars don't have a radiative zone.

The answer is b because c don't explain why the moths are on them and it isn't a because as we know only one species of moth does this