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GEN CHEM I chap 4
Question | Answer | |
---|---|---|
albedo and insolation | 1. Albedo: is relfexion of solar radiation. It prevents absorption of light. 2. Insolation: solar radiation or light and other waves. | |
stoichiometry. What does it allow you to do? | 1.Allows you to: predict the amounts of products that will form in a chemical reaction based on the amount of reactants that react. 2. Also allows us to: determine the amount of reactants necessary to form a given amount of product. | |
Stoichiometry: making pizzas | 1. Stoichiometry is similar to those in a cooking recipee. 2. Is the same as claculating the number of pizzas that can be made from a given amount of cheese. 1 crust+ 5 ounces of sauce+2 cups of cheese= 1 pizza. pg 129 | |
stoichiometry power point definition: | The study of the numerical relationship between chemical quantities in a chemical reaction is called stoichiometry | |
reaction stoichiometry: | The coefficients in a balanced chemical equation specify the relative amounts in moles of each of the substances involved in the reaction 2 C8H18(l) + 25 O2(g) 16 CO2(g) + 18 H2O(g) | 2 molecules of C8H18 react with 25 molecules of O2 to form 16 molecules of CO2 and 18 molecules of H2O 2 moles of C8H18 react with 25 moles of O2 to form 16 moles of CO2 and 18 moles of H2O 2 mol C8H18 : 25 mol O2 : 16 mol CO2 : 18 mol H2O |
predicting amounts of stoichiometry: pg 129 | 2. The amounts of any other substance in a chemical reaction can be determined from the amount of just one substance. | How much CO2 can be made from 22.0 moles of C8H18 in the combustion of C8H18? 2 C8H18(l) + 25 O2(g) 16 CO2(g) + 18 H2O(g) 2 moles C8H18 : 16 moles CO2 |
making molecules: mass to mass conversions: | mass A-->Amount A (in moles)--> Amount B (in moles)-->Mass B | |
1 kg=?g | 1 kg= 1000 g | |
limiting reactant | The tomato sauce limits the amount of pizzas we can make. In chemical reactions we call this the limiting reactant. | When this reactant is used up, the reaction stops and no more product is made The reactant that limits the amount of product is called the limiting reactant sometimes called the limiting reagent the limiting reactant gets completely consumed |
theoretical yield: | The maximum number of pizzas we can make depends on this ingredient. In chemical reactions, we call this the theoretical yield. it also determines the amounts of the other ingredients we will use! (smallest # in answer) | 2. def: The amount of product that can be made from the limiting reactant is called the theoretical yield |
excess reactant | Reactants not completely consumed are called excess reactants | |
summarizing limiting reactant and yield: | 1. The limiting reactant- it the reactant that is completely consumed in a chemical reaction and limits the amount of product. 2. The reactant in excess- is any reactant that occurs in a quantity greater than is required to completely react | with the limiting reactant. 3. The theoretical yield: is the amount of product that can be made in a chemical reaction based on the amount of limiting reactant. |
the actual yield: | is the amount of product actually produced. | |
percent yield: | is calculated as: actual yield/theoretical yeild * 100% | |
theoretical yield: | The theoretical yield will always be the least possible amount of product the theoretical yield will always come from the limiting reactant | |
actual yield: | Because of both controllable and uncontrollable factors, the actual yield of product will always be less than the theoretical yield | |
homogeneous mixture of 2 substances such as salt and water is a? | solution. Homogeneous mixtures are called solutions | |
solute | 1. Is being dissolved by the solvent. 2.The component of the solution that changes state is called the solute | |
solvent: | 1. Is doing the dissolving. 2.The component that keeps its state is called the solvent | |
dilute solutions: | Dilute solutions have a small amount of solute compared to solvent | |
concentrated solutions: | Concentrated solutions have a large amount of solute compared to solvent | |
a common way to express solution concentration is: | molarity (M) | |
Molarity (M) equation: | Molarity (M)= amount of solute (in mol)/volume of solution (in L) | |
solution stoichiometry: | Because molarity relates the moles of solute to the liters of solution, it can be used to convert between amount of reactants and/or products in a chemical reaction Volme A->Amount A (in moles)->Amount B(in moles)->Volume B | |
what happens to a solute when it dissolves? | There are attractive forces between the solute particles holding them together There are also attractive forces between the solvent molecules | When we mix the solute with the solvent, there are attractive forces between the solute particles and the solvent molecules If the attractions between solute and solvent are strong enough, the solute will dissolve |
solute and solvent interactions: | when a solid is put into a solvent, the interactions between solvent and solute particles compet with the interactions among the soluteparticles themselves. | |
electrolytes | Materials that dissolve in water to form a solution that will conduct electricity are called electrolytes | |
nonelectolytes | Materials that dissolve in water to form a solution that will not conduct electricity are called nonelectrolytes | |
strong electrolytes: | substances such as sodium chloride that completely disociate into ions when they dissolve in water are strong electrolytes. | |
a salt is a? | electrolyte that conducts electricity. | |
gentle persuasion | is water. | |
dissociated | completely deconnect. | |
green house gases | 1. Allow sunlight to enter atmosphere and warm earth's surface, but preventing some of the heat generated by sunlight from escaping. 2. If there were no green house gases, it would be much colder. | 3. CO2 is the main green house gas which is caused by natuaral gas, petroleum, and coal. |