Calculate the mass in grams of 1.72×10^24 molecules of formaldehyde. The chemical formula for formaldehyde is CH2O.
1 answer:
Answer: m= 85.8 g CH2O
Explanation: First step is convert the molecules of CH2O to moles using the Avogadro's Number.
1.72x10²⁴ molecules CH2O x 1 mole CH2O / 6.022x10²³ molecules CH2O
= 2.86 moles CH2O
Next is convert the moles of CH2O to mass using the molar mass of CH2O
2.86 moles CH2O x 30 g CH2O / 1 mole CH2O
= 85.8 g CH2O
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Answer: The given quantity is 2 moles of magnesium or 48 g of magnesium.
The unknown quantity is mass of MgO in grams.
Molar mass of MgO = 40 g
Explanation:
As can be seen from the chemical equation, 2 moles of magnesium react with 1 mole of oxygen gas to give 2 moles of MgO.
According to mole concept, 1 mole of every substance weighs equal to its molar mass.
Thus of magnesium produce=
of MgO.
Molar mass is the mass in grams of 1 mole of the substance.
Thus if 2 moles of MgO weigh= 80 g
1 mole of MgO will weigh=
Thus molar mass of MgO is 40 g.