3 Review of Stoichiometry

• Stoichiometry is the calculation of quantitative relationships of the reactants and products in chemical reactions, and it relies on the law of conservation of mass, the law of definite proportions, and the law of multiple proportions.
• The law of conservation of mass states that the total weight of the substances entering into a chemical change is equal to the total weight of the substances produced.
• The law of definite proportions states that when elements combine to form a compound, they do so in a definite proportion by mass.
• The law of multiple proportions states that the masses of one element combined with a fixed mass of another element in a different compound of the two elements are in the ratio of small whole numbers.
• Stoichiometry is often used to balance chemical equations, for example, the two diatomic gases, hydrogen and oxygen, can combine to form a liquid, water.
• To produce 4 moles of water, 4 moles of Hydrogen and 2 moles of Oxygen are needed.
• If we had 50 moles of Hydrogen, we would need 25 moles of Oxygen to react and would produce 50 moles of water.
• In stoichiometric calculations, always start with the given and analyze what the next step is going to be to cancel like terms.
• If we had 3 moles of Oxygen, we would need 6 moles of Hydrogen to react and would produce 6 moles of water.
• 2 moles of Hydrogen and 1 mole of Oxygen are needed to produce water.
• Starting with 1.00 g of C6H12O6, the moles of C6H12O6 can be calculated.
• If you don't have any coefficient, it means 1.
• Coefficient is the number before an element or compound.
• Unang mag-a is the adjustment to the lesser side to balance the equation.
• Stoichiometry is also often used for the molar proportions of elements in stoichiometric compounds, for example, the stoichiometry of hydrogen and oxygen in H2O is 2:1.
• In stoichiometric compounds, the molar proportions are whole numbers, which is what the law of definite proportions is about.
• The mole does not describe the weight or shape of a compound, it describes the quantity.
• Use the coefficients to find the moles of H2O and then turn the moles of water to grams.
• These mole ratios can be used to calculate the moles of one chemical from the given amount of a different chemical.
• Most of the time in chemistry, the amounts are given in grams instead of moles.
• When the limiting ingredient/reactant is already consumed, the reaction stops.
• We use molar mass and the mole ratio to get to moles of the compound of interest.
• Given, the moles of C6H12O6 cancel the g of C6H12O6 by dividing it to the molar mass of C6H12O6 (180 g/ mol).
• The other reactant limits how much product we get.
• This is called the limiting reactant.
• Chlorine is the limiting reactant because it produces less of the product.
• In the reaction 2 Na + Cl2 → 2 NaCl, 1 mol of chlorine is needed to react with 2 moles of sodium.
• We can also start with mass and convert to moles of product or another reactant.
• If you have the limiting reactant, you also have an excess reactant.
• Once it runs out, the reaction stops.
• Molecular mass, molecular weight, are not based on the significant figures of that molecular mass or molecular weight.
• One mole is 6.02 x 10^23.
• The mole is just a number like pounds or yards, the abbreviation for moles is mol.
• The molar mass of a compound can also be calculated by the formula Molar Mass = Summation of all atomic mass divided by the number of atoms in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound.
• The molar mass of a compound can also be calculated by the formula Molar Mass = Summation of all atomic mass divided by the number of atoms in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound.
• The molar mass of calcium chloride, CaCl2, is 40.08 g/mol.
• There are different kinds of mole conversion problems such as moles to grams, moles to molecules, moles to liters, and vice versa.
• The molar mass of a compound can also be calculated by the formula Molar Mass = Summation of all atomic mass divided by the number of atoms in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound.
• The molar mass of a compound can also be calculated by the formula Molar Mass = Summation of all atomic mass divided by the number of atoms in the molecule or compound divided by the moles in the molecule or compound divided by the moles in the molecule or compound.
• The molar mass of a compound can be calculated by the formula Molar Mass = Summation of all atomic mass.