The moles can be defined as the mass of the substance with respect to molar mass. The moles of potassium nitrate is 1 mol.
<h3>How to calculate moles of a substance?</h3>
The moles of a compound can be calculated from:

The molarity can be defined as the moles of solute in a liter of solution.
The molarity can be expressed as:

The molarity of potassium nitrate solution is 2 M, and the volume is 500 mL.
The moles of potassium nitrate is given as:

The moles of potassium nitrate in 2 M, 500 mL solution are 1 mol.
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Answer:
Baking soda has a ph of 9
Explanation:
CuO(aq) + H2(g) → H2O(l) + Cu(s)
CuO= 64 + 16= 80g
1 mole of CuO → 1 mole of Cu
80g of CuO → 1 mole of Cu
20.50g of CuO → y
y= 20.50/80= 0.26mole.
The physical property you measured is the boiling point of the liquid.
Therfore, if the liquid has a boiling point of 100°C, it turns from liquid state to vapor when you heat it up to 100°C.
To conclude, The liquid should be pure water. Because only pure water has a boiling point of 100°C, using this physical property, we can test whatever liquid ans see if it's pure water or not, this test is called the boiling point test.