Calculate the mass of hydrogen produced when 72 g of magnesium reacts with sulfuric acid.
1 answer:
Since this is a single replacement reaction, the equation for the reaction is:
From this, we know that for every mole of magnesium consumed, 1 mole of hydrogen is produced.
The atomic mass of magnesium is 24.305 g/mol, so 72 grams of magnesium is 72/24.305 = 2.9623534252211 moles.
This means we need to find the mass of 2.9623534252211 moles of hydrogen.
Hydrogen has an atomic mass of 1.00794 g/mol, so doubling this to get the formula mass of of , we get 2.01588 g/mol, which his a mass of:
(2.01588)(2.9623534252211). which is about <u>5.97 g</u>
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Answer:
1.155 moles of potassium nitrate are required to make 550 mL of a 2.1M solution.
Explanation:
In a mixture, the chemical present in the greatest amount is called a solvent, while the other components are called solutes.
Molarity is a unit of concentration of a solution and indicates the amount of moles of solute that appear dissolved in each liter of the mixture. In other words, the Molarity (M) or Molar Concentration is the number of moles of solute that are dissolved in a given volume.
The Molarity of a solution is determined by the following expression:
Molarity is expressed in units ().
In this case:
- Molarity= 2.1 M
- number of moles of solute= ?
- Volume= 550 mL= 0.550 L (being 1L=1000 mL)
Replacing:
Solving:
number of moles of solute= 2.1 M* 0.550 L
number of moles of solute= 1.155 moles
1.155 moles of potassium nitrate are required to make 550 mL of a 2.1M solution.