Stoichiometry
Section 11.1 What is stoichiometry?
In your textbook, read about stoichiometry and the balanced equation.
For each statement below, write true or false.
_______true___________ 1. The study of the quantitative relationships between the amounts of reactants used and the amounts of products formed by a chemical reaction is called stoichiometry.
________true__________ 2. Stoichiometry is based on the law of conservation of mass.
_________false_________ 3. In any chemical reaction, the mass of the products is less than the mass of the reactants.
________true__________ 4. The coefficients in a chemical equation represent not only the number of individual particles but also the number of moles of particles.
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2.15 mol O2 . 2 mol H2O/1 mol O2, 4.30 ________________ mol H2O 5. How many moles of water are needed for 0.100 mol of sodium peroxide to react completely in this reaction?
0.100 mol Na2O2 2 mol H2O/2 mol Na2O2, 0.100 ________________ mol H2O 6. How many moles of oxygen are produced if the reaction produces 0.600 mol sodium hydroxide?
0.600 mol NaOH . 1 mol O2/4 mol NaOH, 0.150 ________________ mol O2
Section 11.2 continued
In your textbook, read about mole-to-mass and mass-to-mass conversions.
Solving a mass-to-mass problem requires the four steps listed below. The equations in the boxes show how the four steps are used to solve an example problem. After you have studied the example, solve the problems below, using the four steps.
Example problem: How many grams of carbon dioxide are produced when 20.0 g acetylene (C2H2) is burned?
Step 1 Write a balanced chemical equation for the reaction.
Step 2 Determine the number of moles of the known substance, using mass-to-mole conversion.
Step 3 Determine the number of moles of the unknown substance, using mole-to-mole conversion.
Step 4 Determine the mass of the unknown substance, using mole-to-mass conversion. 7. In some mole-to-mass conversions, the number of moles of the known substance is given. In those conversions, which step of the above solution is not necessary? __________Step 2__________ 8. In a blast furnace, iron and carbon monoxide are produced from the reaction of
Ratio between the amounts in moles of any two compounds involved in a chemical reaction.
7. In a procedure developed to determine the percent zinc in post 1982 pennies, 50 ml of an HCl solution was used to react (dissolve) all of the zinc in the penny. To ensure complete reaction, the solution contains twice as many moles of HCl that is actually needed. What concentration of HCl should be used?
(0.074 mol HCl x 1 mol NaOH) / 1 mol HCl = 0.074 mol NaOH
As a group, we obtained our salt mixture of calcium chloride and potassium oxalate, and weighed the mixture. We were able to make an aqueous solution from the mixture and distilled water. We boiled and filtered off the solution, leaving the precipitate. Once the precipitate was dried overnight, it was weighed and the mass was measured. Then we calculated the moles of the precipitate.
If the relative amount of reactants is altered, then the limiting reactant may change accordingly. For example, a balanced chemical equation of a certain reaction specifies that an equal number of moles of two substances A and B is required. If there are more moles of B than of A, then A is the limiting reactant because it is completely consumed when the reaction stops and there is an excess of B left over.
The purpose of this experiment is to distinguish the relationships between reactants and products, in addition to expanding on concepts such as single displacement reactions, mole ratio values, moles to mass, theoretical yields, limiting reactants, excess, stoichiometric relationships and percentage errors.
A 300.0-mL saturated solution of copper(II) peroidate (Cu(IO4)2) contains 0.38 grams of dissolved salt. Determine the Ksp.
Not all combustion reactions involve organic compounds made of carbon and hydrogen (nonorganic compounds), which means that the products are not always
Stoichiometry is a very important part of chemistry. Stoichiometry refers to calculating the masses of molecules and their products . The reactants are usually given and stoichiometry is used to find the products of the equations as well balancing the equation. An example of this would be sodium chloride (NaCl). Stoichiometry will say that if there are ten thousand atoms of sodium and one atom of chlorine, only one molecule of sodium chloride can be made and that fact can never be changed.
First starting with a balanced equation, a balance equation is equal on each side of the arrow, to then use stoichiometry. Reactants are what elements are being put together to make a chemical reaction and they are placed in front of the arrow. The products are the changed substances left after the reaction. The amount of atoms and charges of elements are matching for the reactants and the
Stoichiometry is a method scientists use to presume how two or more substances will react together. In order to do so successfully, the reactants are positioned on the left and the products on the right. The most important part of successfully
In a chemical reaction, atoms may be rearranged according to their position, but as the law of conservation of mass states, atoms are never created nor destroyed during a reaction. In Chemistry, Stoichiometry can be defined as the observation of the amount of substances used during a reaction. In a reaction a certain number of reactants form a particular amount of product. In the above experiment, the goal was to react copper chloride with sodium phosphate to form Copper (II) phosphate trihydrate. When a chemical reaction is performed in a laboratory, the ratio of the number of reactants used for the reaction is not equal to the stoichiometric ratio of the reaction.
Coefficients show the correct proportions of atoms and molecules in a chemical reaction. They are normal sized numbers placed at the beginning of the chemical formulas in a chemical reaction during the process of balancing. They tell how many of an entire chemical formula is in a reaction.
2. Calculate the mass of the reaction mixture in each reaction first by determining the volume of the solution and then assuming that the density of the solution is the same as pure water (1.0g/ml). Show work here and record your answer in Data Table 2.