The answer is argon, hope this helps!
Answer:
The mass of 1.26 mole of water, H₂O, is 22.68 grams
Explanation:
Molar mass is the amount of mass that a substance contains in one mole. In other words, the molar mass of an atom or a molecule is the mass of one mole of that particle and its unit is g/mole.
In this case, being:
the molar mass of water H₂O is:
H₂O= 2*1 g/mole + 16 g/mole= 18 g/mole
Then you can apply the following rule of three: if 18 grams are present in 1 mole of H2O, how much mass is present in 1.26 moles of water?

mass= 22.68 grams
<u><em>The mass of 1.26 mole of water, H₂O, is 22.68 grams</em></u>
Answer:
Density = 
Explanation:
Given that,
Mass of the object, m = 1000 g
Volume of the block, V = 50 cm³
We need to find the density of the object. Density is equal to mass per unit volume.
d = m/V

So, the density of the object is
.
Answer:
2Mg + O₂ ⟶ 2MgO
Explanation:
Step 1. Start with the most complicated-looking formula (O₂?).
Put a 1 in front of it.
Mg + 1O₂ ⟶ MgO
Step 2. Balance O.
We have fixed 2 O on the left. We need 2O on the right. Put a 2 in front of MgO.
Mg + 1O₂ ⟶ 2MgO
Step 3. Balance Mg.
We have fixed 2 Mg on the right-hand side. We need 2 Mg atoms on the left. Put a 2 in front of Mg.
2Mg + 1O₂ ⟶ 2MgO
Every formula now has a coefficient. The equation should be balanced. Let’s check.
<u>Atom</u> <u>On the left</u> <u>On the righ</u>t
Mg 2 2
O 2 2
All atoms are balanced.
The balanced equation is
2Mg + O₂ ⟶ 2MgO