You have to note that pure substances can be elements or compounds. There is only one component all throughout. On the other hand, a mixture is a combination of different elements and compounds. They can appear in different phases. For example, air is a mixture. It is composed of pure substances of oxygen, carbon dioxide, and nitrogen.
Answer: Number of molecules of hydrogen gas 
Explanation:
Number of moles of sodium =
According to reaction , 2 moles of sodium produces 1 mole of hydrogen gas , then 2.11 mol of sodium will= 
of hydrogen gas that is 1.05 moles of hydrogen gas.
Number of molecules = 
moles of substance
Moles of hydrogen gas formed = 1.05 moles
Number of molecules of hydrogen gas = 
moles of hydrogen gas
Number of molecules of hydrogen gas 
A solution is a homogeneous type of mixture of two or more substances. A solution has two parts: a solute and a solvent.
A whole number, not a fraction, that can be negative, positive or zero are integers. They cannot have decimal places.
Now, converting 0.000431 L to decimal an integer as:
Since, 
So, 
.
Hence, the integer value for 0.000431 L is 
.
Answer:
14. 13.2cg = 1.32dg
15. 3.8m = 0.0038km
16. 24.8L = 24800mL
17. 0.87kL = 870L
18. 26.01cm = 0.0002601km
19. 0.001hm = 10cm
Explanation:
14. 13.2/10 = 1.32
15. 38/1000 = 0.0038
16. 24.8(1000) = 24,800
17. 0.87(1000) = 870
18. 26.01/100000 = 0.0002601
19. 0.001hm(10000) = 10
An easy way to do these by yourself is to familiarize yourself with what each prefix means. Once you do this, you can multiply the value of the prefix when converting from a smaller unit of measurement to a larger one and divide the value of the prefix when converting from a large unit of measurement to a smaller one.
