How many moles of NaCl are in 1.25 L of a 0.330 M NaCl solution?

0.4 moles

Explanation:

Given that,

Amount of moles of NaCl (n) = ?

Volume of Nacl solution (v) = 1.25 L

Concentration of NaCl solution (c) = 0.330 M

Since concentration (c) is obtained by dividing the amount of solute dissolved by the volume of solvent, hence

c = n / v

Make n the subject formula

n = c x v

n = 0.330 M x 1.25 L

n = 0.4125 moles (To 2 significant figures, n becomes 0.4 moles)

Thus, 0.4 moles of NaCl are in 1.25 L of a 0.330 M NaCl solution

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.