Decreasing Pressure. The combined gas law states that the pressure of a gas is inversely related to the volume and directly related to the temperature. If temperature is held constant, the equation is reduced to Boyle's law. <em>Therefore, if you decrease the pressure of a fixed amount of gas, its volume will increase.</em>
<em>thanxx</em>
<em>moderator will see it i bett and will delete itt</em>
Answer:
The result is 3.859 in which we use four significant figures.
Explanation:
We start by solving the mathematical operation :

The result for the operation is 3.859438 but the numbers in the operation are given with four significant figures and that is why we are going to use four significant figures to express the result
To express 3.859438 with four significant figures we use the first four digits that appear from left to right starting by the first digit that is different to zero
In this case : 3.859 will be the result with four significant figures.
We also use a rule that says : To decide if the last significant figure remains the same we look for the value of the digit at its right.
If that number is greater than or equal to 5 ⇒ we sum one to the last significant figure
For example 3.859738 = 3.860 with four significant figures because the ''7'' is greater that 5
If that number is less than 5 ⇒ the last significant figure remains the same
In our case : 3.859438 = 3.859 because ''4'' is less than ''5''
<u>Answer:</u> The correct answer is 
<u>Explanation:</u>
We are given:
Moles of hydrogen gas = 4 moles
As, oxygen is given in excess. Thus, is considered as an excess reagent and hydrogen is considered as a limiting reagent because it limits the formation of products.
For the given chemical equation:

By Stoichiometry of the reaction:
2 moles of hydrogen produces 2 moles of water molecule.
So, 4 moles of hydrogen will produce =
of water.
Hence, the correct answer is 