Answer
a.) 4.01 x $10^{22}$ atoms
b.) 6.00 x $10^{22}$ atoms
c.) 3.67 x $10^{22}$ atoms
d.) 6.55 x $10^{22}$ atoms
Work Step by Step
a.) $\frac{5.00 g C_{2}H_{5}O_{2}N}{1}$$\times$$\frac{1 mol C_{2}H_{5}O_{2}N}{75.07 g C_{2}H_{5}O_{2}N}$$\times$$\frac{1 mol N}{1 mol C_{2}H_{5}O_{2}N}$$\times$$\frac{6.022 x 10^{23} atoms}{1 mol N}$
b.) $\frac{5.00 g Mg_{3}N_{2}}{1}$$\times$$\frac{1 mol Mg_{3}N_{2}}{100.95 g Mg_{3}N_{2}}$$\times$$\frac{2 mol N^{3+}}{1 mol Mg_{3}N_{2}}$$\times$$\frac{6.022 x 10^{23} atoms}{1 mol N^{3+}}$
c.) $\frac{5.00 g Ca(NO_{3})_{2}}{1}$$\times$$\frac{1 mol Ca(NO_{3})_{2}}{164.04 g Ca(NO_{3})_{2}}$$\times$$\frac{2 mol N^{5+}}{1 mol Ca(NO_{3})_{2}}$$\times$$\frac{6.022 x 10^{23} atoms}{1 mol N^{5+}}$
d.) $\frac{5.00 g N_{2}O_{4}}{1}$$\times$$\frac{1 mol N_{2}O_{4}}{91.98 g N_{2}O_{4}}$$\times$$\frac{2 mol N^{4+}}{1 mol N_{2}O_{4}}$$\times$$\frac{6.022 x 10^{23} atoms}{1 mol N^{4+}}$
