# Question #c7f43

##### 1 Answer

Your gas contains

#### Explanation:

The first important thing to notice is that the gas is tetra-atomic, *every molecule* of gas contains **4 atoms**.

So, if you know how many molecules you have, you can determine how many atoms are present by multiplying that number by **4**.

In order to get the number of molecules, you need the number of moles of gas first. Notice that the temperature of the gas is **273.15 K**, and that its pressure is **76 cmHg**, which is equivalent to **1 atm**.

These are actually the old conditions given for **STP**, which implies that *1 mole* of your gas will occupy exactly **22.4 L** - this is known as the molar volume of gas at STP.

SInce you're dealing with a volume of **1.4 L**, the number of moles of gas present is

To get the number of *molecules* present in this many moles, use the fact that *1 mole* of a substance contains exactly **Avogadro's number**.

Finally, get the number of atoms by multiplying this number by **4**

I'll leave the answer rounded to two sig figs