A sample of the Earth’s crust was found to contain over 80% of a material called silicon dioxide. The sample had a volume of 15 cm3 and the mass of the sample was 39.75 grams. What is the density of silicon dioxide? Show all work and provide units in your answer.

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).