Lessons 9-11

Lesson 9

Lesson 9 talks more about moles. A mole is also Avogadro's number. 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.

Practice Problems

1. The average mass of atoms of an element is listed on the periodic table.

Lesson 10

Lesson ten was more about converting grams, moles, and molar mass. This is where we really put the knowledge we gained in lesson 9 to practice. The most important thing to remember here is to label your numbers with units and make sure your units cancel out.

Practice Problem

5. A) 10 g calcium, Ca

B) 5 g sodium fluoride, NaF

C) 2 g iron oxide, FeO

Lesson 11

Lesson eleven continues to talk about converting mass and molar mass and moles. There is practice problem pictured below.

 

 

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Lessons 7 and 8

In lesson 7 we learned about lethal doses. A lethal dose is an amount of an ingested substance that kills 50% of a test sample of animals. This is expressed in mg/kg. The lethal dose depends on the amount of a substance and the mass of the organism. The smaller the amount the more toxic it is.

Practice Problems

1. The toxicity of different substances is usually measured by exposing lab animals to the substance in different amounts.

 

Lesson 8

In lesson eight we learned about percent error. We did a lab where we had to try and figure out how many small objects were in a Baggie. Then when we learned the correct method we we taught the equation for percent error. This equation is pictured below.

Practice Problems

5. The marbles will have a greater mass because the mass of a marble is greater than the mass of a plastic bead.

 

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Disappearing Spoon: Intro - Chapter 2

The introduction of this book gives the backround of what made the author curious about elements. When he was young and got sick his mother would use a mercury thermometer to take his temperature. Being tha talkative child he was, the thermometer would often fall from his mouth and shatter, sending mercury everywhere. How mercury acted when loose is what intrigued him about science. Chapter one sets the periodic table up the the U.S. It talks about several different elements and where they would be in relation to a map of the U.S. Easch example has a little backround information as well. When talking about Helium, the author also talks about Plato and his philosphies and how they are similiar to Helium. To help understand the noble gases, Maria Goeppert-Mayer is focused on. She helped to create the ideas behind electron shells that we use today. On top of the backround ifo the book also teaches about the table and how it's set up, isotopes and a little about elcetron configuration. Chapter two talks about carbon, silicon and germanium. Carbon is the basis of life. It creates essential amino acids in carbon chains and produces life. Below carbon is silicon, a cousin of somesorts of carbon. Silicon is very similiar to carbon except that it is a solid at human temperatures instead of a gas. Silicon has the potential to carry life but because of it's phase it never will. Lower in the same column is germanium, an element that was experimented with as a semi conductor. The results were disasterous and germanium's name was scarred from ever having life potential like carbon.

Lesson 6

Today we learned about the different types of chemical reactions. They follow these patterns.
Combination: A+B => AB
Decomposition: AB => A+B
Single Exchange: A + BC => AC + B
Double Exchange: AB + CD => AC + BD

Practice Problems
3A. NaOH (aq)+ HNO3 (aq) => NaOH3 + H2 (l)

Lessons 3-5

Lesson 3
Lesson 3 describes the differences between physical and chemical changes. A physical change is a change in matter in which a substance changes form but not identity. A chemical change is a change in matter that results in the formation of a new substance with new properties. Dissolving is considered a physical change. However, ionic compounds do not dissolve the same way as molecular solids.

Practice Problems
6A. Chemical, the equation has changed
6B. Physical, it is the same compound

Lesson 4
Lesson 4 was about the law of conservation of mass. this law states that mass can not be created or destroyed in a physical or chemical change. The exception to this is when you have a gas product. If the gas is not trapped some mass will be lost because it is impossible to account for all gas mass if it is not contained. Individual atoms are conserved in chemical reactions and physical changes. From start to finish the number of atoms in each element stays the same.

Practice Problem
4. C

Lesson 5
Lesson 5 taught us how to balance  chemical equations. To do this always start with the element that only shows up once on each side of the equation. Also when balancing equations you can only change the coefficient.

Practice Problem
1. Chemical equations need to be balanced because mass cannot be created or deswtroyed during the change.

Unit 4 Lessons 1 and 2

Lesson 1
Unit 4 is about toxins which are things that interact with living organisims and can cause harm. Toxins can enter the body by inhaling them, ingesting them or through the skin. Then we talked about how to interpret a chemical equation. there is an example pictured below.

Practice Problems
1. Reactants are the things that combine to form something in a chemical equation. The thing that it forms is called the product.
3. A toxic substance is something that can enter the body and cause harm.

Lesson 2
Lesson two talks more about chemical equations. Chemical equations allow chemists to track and predict changes in matter.

Practice Problem
3A. A solid and an aqueous solution combine to form an aqueous solution and gas.

Unit 3 Review

Lessons 1-4
In these lessons we learned about weather, proportions, density and temperature scales. By learning terms like cold front, low pressure and jet stream we are now able to more easily understand weather and the things that cause it. We learned about the proportionality constant k, which allows us to use other formulas to find volume, pressure and temperature. Then we learned that density= mass/volume. Next we learned the melting and boiling points of the three most common temperature scales used: Farenheit, celcius and kelvin. A picture below describes this in more depth.

Lessons 5-7
We learned how to covert celcius to kelvin by using the equation K=C+273.  We also talked about how gas particles are in constant random motion. when the temperature increases the gas particles speed up. Then we learned that in Charles's Law, volume is proportional to temperature. When temperature increases volume does as well but density decreases. Next we learned about fronts. When cold air overtakes warm air it is a cold front. When warm air takes over cold air it is a warm front.

Lessons 8-10
Sublimation is the change from a solid to a gas. Next we learned that atmospheric pressure is air pressure that's always present on Earth as a result of air molecules hitting surfaces of objects on earth. At sea level and 25C there is 14.7lb/in2 of air pressure from the air around us. This is 1 atm. Next we talked about Boyle's law. Boyle's Law states that the pressure of a given amount of gas is inversely proportional to its volume if the temperature and amount of gas are not changed.

 

 

 

Lessons 11 and 12

In lesson 11 we learned that stated in Boyle's Law the pressure of a given amount of gas is directly proportional to temperature if the gas volume and amount of gas do not change. Temperature must be Kelvin.  We also learned the differences between rigid and flexible containers. Flexible Container: Changing temp or pressure to make the volume change. Charles' law applies when pressure is the constant. Boyle's law applies when temperature is the constant. Rigid Container: Changing the temperature or pressure. Volume is a constant. Applies to Gay-Lussac's law. Then we learned that gas pressure is the force of gas molecules hitting the walls of its container.

 

 

Lessons 13-16

The combined gas law is written as k=PV/T. Then we learned that clouds form when water vapor condenses and forms water droplets. Must have something to condense on. Clouds form when water vapor condenses and forms water droplets. Next we talked about air pressure, which can be determined by measuing the height of a liquid in a container. And finally we talked about moles.  A mole is a unit used to keep track of very large numbers.

1 mole = 602,200,000,000,000,000,000,000 We also learned about standard temperature and pressure (STP). 1 atm = 273 K and 1 mole = 22.4 L at atm. Equal volumes of gases have equal numbers of gas particles if temperature and pressure are the same.


 

Lessons 17 and 18

The ideal gas law has a constant R which is always equal to .082, the equation is pictured below. The equation can be rearranged to solve for any variables and n represents the number of moles. Then we talked about humidity, the amount of water vapor in the air. Relative humidity is the amount of water vapor in the air compared to the maximum amount of water vapor possible temperature. This is expressed in %.

 

 

 

Lesson 19

This lesson talked about hurricanes which are giant stroms that consist of heavy rains and intense high winds.  They form over areas where warm water evaporates into the air and are measured on a scale of 1-5 from least to most severe. The picture below decribes how storms turn into hurricanes.







 

 Practice Problems:



Lesson 18

Today we learned about humidity. Humidity is the density of water viper in the air at any time. It is dependent on air temperature and air pressure. Condensation proves that there is water in the air. The temperature where water vapor condenses tells how much water vapor is in the air. We also learned about relative humidity. Relative humidity is the amount of water vapor in the air compared to the maximum amount of water vapor possible temperature. This is expressed in %.

 

Practice Problems

Why does condensation prove there is water in the air?

The water in the air hits the cold water in a glass and condenses because of the change in temperature, allowing the water vapor to condense onto something.

 

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Lessons 17 and 19

Lesson 17

In lesson 17 we learned about the ideal gas law. The equation for this law is pictured below. You can also rearrange the equation to solve for any variable. R is the constant in this law and is always equal to 0.082. n is the variable representing the number of moles.

Practice Problems

 

Lesson 19

In lesson 19 we learned about hurricanes. Hurricanes are composed of large winds and heavy rain. They form when warm water evaporates into the atmosphere. The severity of a hurricane is measured on a scale of 1-5, 1 is the lowest and 5 is the most severe. There is a picture below that describes how storms turn into hurricanes.

Practice Problem

1. Hurricanes form over warm oceans and it must be at least 80 degrees Fahrenheit with lots of moisture in the air.

 

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Lessons 15 and 16

Lesson 15
In this lesson we learned about number density and air pressure. Air pressure can be determined by measuring the difference in height of a liquid. We also learned the formula for number density, which is pictured below.

Practice Problems
1. Air is less dense as altitude increases. Both the pressure and temperature is less as atltitude increases.


Lesson 16
In this lesson we learned about moles. A mole is a unit used to keep track of very large numbers.
1 mole= 602,200,000,000,000,000,000,000 We also learned about standard temperature and pressure (STP). 1 atm = 273 K and 1 mole = 22.4 L at atm. Equal volumes of gases have equal numbers of gas particles if temperature and pressure are the same.

Practice Problems
1. Chemists invented the mole in order to keep track of the insanely large number of particles in substances

Lessons 13-14

Lesson 12

Today we learned about the combined gas law. The combined gas law is displayed as

 

Or

 

 

 

 

 

 

 

 

 

 

Use if volume, pressure and temperature all vary


Increase in altitude causes a decrease in temperature and pressure

 

Lesson 13

Clouds form when water vapor condenses and forms water droplets. Must have something to condense on. Clouds form when water vapor condenses and forms water droplets. Must have something to condense on.

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Section 12

Today we learned more about the molecular view of gas pressure. Gas pressure is the result of gas molecules striking the walls of a container.A decrease in volume increases the frequency of collisions. This means that the gas pressure will then increase because of the faster motion of molecules.

Practice Problems
3. When the temperature increases, gas particles get excited and move faster causing it to expand.

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Lesson 11

Gay-Lussac's Law: The pressure of a given amount of gas is directly proportional to temperature if the gas volume and amount of gas do not change. Temperature must be Kelvin.

Flexible Container: Changing temp or pressure to make the volume change. Charles' law applies when pressure is the constant. Boyle's law applies when temperature is the constant.

Rigid Container: Changing the temperature or pressure. Volume is a constant. Applies to Gay-Lussac's law.

Practice Problems
2. A flexible container requires changing the temperature of pressure to make the volume change. When pressure is constant Charles' law applies and when temperature is constant Boyle's law applies. A rigid container only applies to Gay-Lussac's law because volume is the constant because in a rigid container there is now where to gain or lose volume.
3. 720L

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Lessons 8-10

Lesson 8

We learned that sublimation is to change from a solid to a gas and that is the case for dry ice. We did a lab where we placed dry ice into an airtight bag and then measured the density of the bag once the dry ice had sublimed. Fog seen around dry ice is actually tiny water droplets.

Evaporation: Phase change from a liquid to a gas.

%error= experimental value - accepted value/ accepted value *100

Gas molecules are about 1000x more dispersed than those of a solid.

 Practice Problems
1. A solid is more dense than a gas because the molecules of a solid are packed closer together.
3. Sublimation is where a solid changes to a gas and evaporation is when a liquid turns to a gas.

Lesson 9

Pressure: Force applied over a certain area. Force per unit area. Gas pressure is caused by gas molecules striking objects or the walls of a container.

Mixtures of all gases that surround you at all times is called the atmosphere.

Atmospheric pressure: Air pressure that's always present on Earth as a result of air molecules hitting surfaces of objects on earth. At sea level and 25C there is 14.7lb/in2 of air pressure from the air around us. This is 1 atm.

Practice Problems
2. Air pressure is when gas molecules hit other things.



Lesson 10

When volume of a gas decreases the pressure increases.

Inverse proportion: 2 variables are inversely proportional to each other if one variable increases as the other decreases.

PV=k or P=k/V Boyle's Law, the relationship between pressure and volume.

Boyle's Law: The pressure of a given amount of gas is inversely proportional to its volume if the temperature and amount of gas are not changed. The equation is above.

Practice Problems
5. Between gas pressure and temperature it is inversely proportional. The relationship between gas pressure and volume is directly proportional.

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