molar mass

303.27 g/mol

255.27 g/mol

163.87 g/mol

372.27 g/mol

$$2.50g\ Na\ \times\frac{22.99\ mol\ Na}{1\ g\ Na}=$$  

$$2.50\ g\ Na\ \times\frac{1\ mol\ Na}{22.99\ g\ Na}=$$  

$$2.50\ g\ Na\ \times\frac{22.99\ g\ Na}{1\ mol\ Na}=$$  

$$2.50\ g\ Na\ \times\frac{1\ g\ Na\ }{22.99\ mol\ Na}=$$  

113.97 g/mol

137.99 g/mol

233.99 g/mol

185.99 g/mol

$$0.55\ mol\ Si\ \times\ \frac{28.09\ g\ Si}{1\ mol\ Si}\ =\$$  

$$0.55\ mol\ Si\ \times\frac{1\ g\ Si\ }{28.09\ mol\ Si}=$$  

$$0.55\ mol\ Si\ \times\frac{28.09\ mol\ Si}{1\ g\ Si}=$$  

$$0.55\ mol\ Si\ \times\frac{1\ mol\ Si}{28.09\ g\ Si}=$$  

$$3.80\ mol\ Ca\ \times\frac{40.08\ g\ Ca}{1\ mol\ Ca}=$$  

$$3.80\ mol\ Ca\ \times\frac{6.022\ x\ 10^{23\ }atoms\ Ca}{1\ mol\ Ca}=$$  

$$3.80\ mol\ Ca\ \times\frac{1\ g\ Ca}{40.08\ mol\ Ca}=$$  

$$3.80\ mol\ Ca\ \times\frac{1\ atoms\ Ca}{6.022\ x\ 10^{23}\ mol\ Ca}=$$