Answer:
2.8 x 10²³ molecules H₂O
1.4 x 10²³ molecules O₂
Explanation:
First, you will need the balanced chemical equation for the formation of water:
2H₂ + O₂ -> 2H₂O
This will help in determining the mole ratios between water and oxygen, which we will need later.
Let's first calculate the number of H₂O (water) molecules. This will require stoichiometry. We are also given the mass, so we must convert mass into moles, then moles into molecules. mass -> moles -> molecules
8.5 g H₂O x (1 mol H₂O/18.01528 g H₂O) x (6.02 x 10²³ molecules H₂O/1 mol H₂O) = 2.8404 x 10²³ molecules H₂O
Rounded to 2 significant digits: 2.8 x 10²³ molecules H₂O
Now, to find the molecules of water, we can begin with the same stoichiometric equation, but before we convert to molecules, we will have to convert moles of water to moles of oxygen. This is where we will use the mole ratio of water to oxygen we got from the balanced chemical equation earlier. 2H₂O:1O₂
8.5 g H₂O x (1 mol H₂O/18.01528 g H₂O) x (1 mol O₂/2 mol H₂O) x (6.02 x 10²³ molecules O₂/1 mol O₂) = 1.4202 x 10²³ molecules O₂
Rounded to 2 significant digits: 1.4 x 10²³ molecules O₂
Answer: 149
Explanation:
Using the ideal gas equation; PV = nRT
P= Pressure = 0.910 atm, T= Temperature = ?
V= Volume = 4.0L R = Gas constant = 0.08206 L.atm/mol/K
n = number of moles = 0.297
Making 'T' the subject of the formular, we have;
T = P V/ n R = 0.910 x 4 / 0.297 x 0.08206
= 149
