Answer:
It s a pure substance.
Explanation:
Can only be separated into its different elements by chemical means because it is connected by a chemical bond.
Answer:
Unlike isopropanol, hydrogen peroxide is not a type of alcohol. You might recognize its chemical formula, H2O2, as being similar to that of water (H2O). The difference is that hydrogen peroxide has two oxygen atoms instead of one. That one extra oxygen atom makes it a strong oxidizer.
Standard temperature is 273 K
Standard pressure is 1 atm
We use the ideal gas equation to find out density of nitrogen gas in g/L
Ideal gas equation:

Molar mass of 
Pressure = 1 atm
Temperature = 273 K

= 1.25 g/L
Therefore, density of nitrogen gas at STP is 1.25 g/L
1. they work ways faster
2. you don't need 100 people making the same thing at once
3. its a better chance of not getting an injury