The number of mercury atoms required to produce 3.49 L of H2 gas according to the equation would be 1.89 x 
From the balanced equation of the reaction:

2 moles of Hg are required to produce 1 mole of the H2 gas.
3.49 L of H2 gas was produced and the density of the gas is 0.0899 g/L
Recall that: density = mass/volume
Mass of the H2 gas = density x volume
= 3.49 x 0.0899
= 0.3138 g of H2 gas
Mole of 0.3138 g of H2 gas = mass/molar mass
= 0.3138/2
= 0.1569 mole
Since the ratio of Hg to H2 according to the equation is 2:1, it means that the mole of Hg is twice the mole of H2.
Thus, mole of Hg = 0.1569 x 2
= 0.3138 mole
According to Avogadro, 1 mole of a substance = 6.022×10^23
0.3138 mole would be:
0.3138 x 6.022 x 10^23
= 1.89 x 
More on the number of atoms in molecules can be found here: brainly.com/question/19036641
It has different reasons. the temperature difference is basically the main reason why the earth atmosphere has layers.
Theoretically the temperature varies because of the different molecules and atoms. for instance the first layer known as troposphere has the greenhouse effect of CO2,CH4, etc. and is covered with a layer of O3...
Answer:
A
Explanation:
When a reaction happens some of the reactants mass is released as energy so the mass of the product would be less
Answer:
The pressure of a given amount of gas is directly proportional to iys absolute temperature provided that that the volume does not change