First calculate for the molar mass of the given formula unit, CaCO₃. This can be done by adding up the product when the number of atom is multiplied to its individual molar mass as shown below.
molar mass of CaCO₃ = (1 mol Ca)(40 g Ca/mol Ca) + (1 mol C)(12 g of C/1 mol of C) + (3 mols of O)(16 g O/1 mol O) = 100 g/mol of CaCO₃
Then, divide the given amount of substance by the calculated molar mass.
number of moles = (20 g)(1 mol of CaCO₃/100 g)
number of moles = 0.2 moles of CaCO₃
<em>Answer: 0.2 moles</em>
a balanced chemical equation occurs when the number of the atoms involved in the reactants side is equal to the number of atoms in the products side.
Answer:
Explanation:
The law of conservation of mass states that mass is neither created nor destroyed during a chemical reaction. This can be gleaned from the third postulate in Dalton's series. Magnesium oxide decomposes into magnesium and oxygen. If 4.03 g of magnesium oxide decomposes to form 2.43 g of magnesium, what mass of oxygen gas is also released in the reaction
The word say magnesium oxide decomposes to magnesium and oxygen
the chemical symbols say
MgO-----------> Mg + O2 (since natural oxygen is diatomic)
the balanced equation says
2MgO-------------->2Mg + O2
4.03 gm----------> 2.43 + ?0 gms
tour high school Algebra I class says
? = 4.03 -2.43 =1.60
your chemical analytcal lab says %mO in MgO = 16/40.3 = 39.7%
your calculator says
39.7/100 X 4.03 = 1.60
all of these prove the law of conservation of mass
