Lessons 1 and 2
Lesson one introduces the unit and defines toxins as harmful substances that can harm and enter the body in many ways. Lesson two goes into the chemical equations of these toxins. Equations help scientists predict and track chemical changes.
Practice Problem
3A. A solid and an aqueous solution combine to form an aqueous solution and gas.
Lessons 3-6
Lesson 3 was about physical and chemical changes. A physical change is a change in matter in which a substance changes form but not identity.(Dissolving) A chemical change is a change in matter that results in the formation of a new substance with new properties. Lesson 4 is about the law of conservation of mass which states that matter can't be created or destroyed during a chemical reaction. And then lesson 5 taught us how to balance equations, when doing so you can only change the coefficient. Lesson six went into further detail about chemical equations and classifying them into 4 major groups:
Combination: A+B => AB
Decomposition: AB => A+B
Single Exchange: A + BC => AC + B
Double Exchange: AB + CD => AC + BD
Practice Problem
3A. NaOH (aq)+ HNO3 (aq) => NaOH3 + H2 (l)
Lessons 7-8
Lesson 7 was about lethal doses, which is an amount of an ingested substance that kills 50% of a test sample of animals. (mg/kg) The smaller the dose the more toxic it is. Then lesson 8 was about percent error. There is a picture of the equation below.
Lessons 9-11
Lesson 9 talks more about moles. The mass of 1
mole is equal to the molar mass. Then on the periodic table the atomic mass is
equal to 1 mole of atoms of the element in grams. You use molar mass to convert
between moles of atoms and grams of atoms. Lesson 10 put our skills to the test and we had to make sure to remember to label our numbers with units
and make sure our units cancel out. And lesson 11 continued on with this theme so heres some practice problems.
Lesson 12-15
In lesson 12 we learned that aspartame is much sweeter than fructose. The smaller the LD50 the more toxic it is. LD50 values are of limited use in determining the long term effects of a substance. Even if you don't reach the actual LD50 there could be very serious long term effects that are not accounted for in the LD50. In lesson 13 we learned that a solute is a substance dissolved in a solution. A solvent is the substance in which a solute dissolves. ( A flute in a vent!) And that molecules in a high concentration area move to areas of lesser concentration. (Molarity) In lesson 4 we put our new found skills to the test.
Lessons 15-19
The biggest thing we learned in lesson 15 was that you can use a hydrometer to
test the molarity of the substance. In this next lesson we basically used all the
knowledge we've gained from throughout the chapter to solve problems. We also
did an activity where we had to try and figure out which solutions were which
by weighing them and accounting for the molar mass.
In lesson 17 we learned that an indicator is molecular substance that changes color
when it comes into contact with an acid or a base.
Acids and bases are corrosive.
When pH is 7 it is neutral or pure water. Below 7 is an acid and above 7 is a
base. This is a picture of the pH scale.
.
These pH
solutions are classified by their colors you can observe. Acids
and bases change the color of indicators.
.
Lesson 18 taught us about
cabbage juice and its indicator colors. Cabbage Juice: Pink=acidic, Green=basic,
Purple=neutral. Substances that add H+ (just one proton) to a
solution are acids. Bases are substances that add OH- to a
solution. Substances that don't add H+ or OH- to the
solution are neutral.
- Arrhenius Definition: An acid is any substance that adds hydrogen ion to solution. A base is any substance that adds hydroxide ion to a solution.
- Brønsted-Lowry Definition- An acid is a proton donor. A base is a proton acceptor.
The products of a reaction is always
called a conjugate.
Lesson 19 talked more about the pH
scale. The pH scale is a logarithmic scale the describes the concentration of H+
ions. pH is related to H+ by the formula: pH=-log[H+] Water
dissociates into H+ and OH- ions. Below is a picture of the pH scale and
examples of substances that fit into each pH level.
Practice Problems
7. The NaBr would weigh
the most because it has more solute than NaOH. The KCl weighs half as much as
the other two because, 500 mL is less than 1 L or 1000 mL.
1. A base is a substance that adds a OH- ion to a substance and an acid is a substance that adds a H+ ion to a substance
Lessons 20-25
Lesson 20 was about dilution. When you dilute something you make it either less basic or less acidic. 7 is the neutral number in the pH scale and by diluting a solution you can approach 7 but you can't turn an acid into a base and visa versa by dilution. We also learned that between each number on the pH scale there is a 10 fold. Then we learned about neutralization, which is when a strong base and a strong acid react and form ionic salt and water. We also learned that when two compounds have the same volumes and the same molarity they have the same number of moles. When this happens its neutral. Then in lesson 22 we learned that titration is the neutralization process between a strong acid and base. When a strong acid is mixed with a weak base there isn't enough OH- ions to neutralize all of the H+ ions so the solution will not be neutral. It will however, be closer to 7 than either starting solution. In lesson 23 we learned about precipitates, which are solids that are produced in a chemical reaction between two solutions. Sometimes The mixing of two ionic solutions results in the formation of a solid. The degree to which a compound dissolves in water is called it's solubility and precipitation is not limited to solids. Lesson 24 was all about molar ratios. A mole ratio is a ratio given by the coefficients in a balanced equation.
Lesson 25 basically continued to break down the mole tunnel and mole ratios into 3 steps. The mole tunnel is just the way you set up your equation to solve mole ratio problems. First, convert grams to moles. Next, find the molar ratio, and last convert grams into moles. ANd finally lesson 26 was abput percent yield which is The equation for percent yield is the actual amount, divided by the theoretical amount and multiplied by 100.
Practice Problems
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