Lesson 11

Lesson 11 was really short! Basically all you need to know is that molar mass values allow you to convert between mass (g) and moles of a substance. In order to do this, you divide the mass of a sample by the molar mass, to convert moles to mass, you multiply the number of moles of the substance by its molar mass. Use the chart for this!! Homework below :) Happy Halloween!!!

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Lesson 9 and 10:

Today we went over lesson 9 and 10! In lesson 9, we covered scientific notation which is a number in standard notation can be converted to scientific notation by writing it as a decimal with one digit to the left of the decimal point times a power of ten. Ex. 1.56*10^4= 15600. Then we went over molar mass, which is the mass of one mol of a substance. The atomic mass given on the table is equivalent to the mass of 1 mol of atoms of the element in grams, which is molar mass. Molar mass allows you to convert between moles of atoms and grams of atoms.

In lesson 10, we continued with moles. A mole of any gas, if it is standard temperature pressure, it always has a volume of 22.4L(important!). Also, chemists use moles of a substance rather than masses because moles are a good way of counting atoms, molecules, or units. The molar mass of a compound is the sum of the molar masses of the atoms in the compound.

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Lesson 8:

Lesson 8 was very short! All we did was learn about percent error. Which is what chemists use to express how close their measurements are to the accepted value. The formula looks like this:

percent error =observed value- actual value times 100 decides by the actual value.

We also did a lab, we received a baggy with something in it, and we had to figure out how many of that substance was in the baggy without counting them. The correct way to do this was by averaging it. Homework below!

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Disappearing Spoon- intro-chapter 2:

Disappearing Spoon started out with an intriguing story of a child who was fascinated with mercury, and then led into other stories and basically just introduced the style of writing in which the author uses and how the book will unravel! In chapter one, it began by explaining the periodic table, and at first stripping away the elements to simply understand the chart itself. After that interesting insight into the periodic table, the author began a very useful metaphor comparing an ancient man Plato and the elements on the periodic table because of the love and erotic dialogue Plato used to use, and the need for most elements to be "completed". However, that doesn't mean all the elements. Helium is the most independent element because it doesn't feel the need or desire as the other elements do to be completed and that goes for all the elements below helium. Then another story arose about a women who could not be taken seriously in the science world even though she was brilliant. Later in the chapter she finally gets a job as a professor, yet isn't paid. She eventually wins a Nobel prize! The chapter covered elements He,B,Sb,Tm,O, and Ho. The next chapter was much more interesting to me! It began talking about the longest words in history and the longest word existed in 1892. These long words were describing proteins. Then it dove into Carbon. Carbon can form from many directions and because of this, it is very steady and stable. This lead to silicon which is carbons copy. And with that, many scientists wonder about life elsewhere because of how closely related carbon and silicon are. Then we dove into silicon. Silicon is everywhere in everyday life. It is used in computers, microchips, cars, calculators ect. Silicon semiconductors sent men to the moon! And drive the most used in everyday life, Internet. Then, the story of how silicon is used and how germanium got kicked out and isn't used. This story talked about a scientist how spend a lot of time experimenting with germanium and gave up. Then two other scientists began and found that silicon worked better. Something super interesting I found out is that volcanoes spew silicon in chunks and the human body cannot distinguish the difference between carbon and silicon so many people breath it in and it is fetal. Scientists think this may be how dinosaurs died millions of years ago! Loved that fact :) then the story went deeper into the story of how the first chips were made. Onto chapter 3! Tell ya about it next Monday :) hope you all had a great week! And weekend. :)

 

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Section 2! Lesson 7:

Lesson 7 covered mostly lethal doses and how to convert them. The definition of lethal dose or LD50: the amount of an ingested substance that kills 50% of a test sample of animals:(. It is expressed in mg/kg, or milligrams of a substance per kilogram of body weight. Also, toxicity depends on the amount of toxic substance and mass of the organism. Thats why to find out, we need to conduct a conversion. The smaller the lethal dose, or LD50, the more potentially dangerous a substance is<--- important!! Lastly, many toxic substances can be therapeutic at lower doses! Below is a conversion so you can see how to do it!

132Ibs 1kg 7069mg = 424,000mg

2.2Ibs 1kg

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Lesson 6!

In lesson 6, we looked closer at chemical equations. Some important things to know is that a combination looks like: A+B--->AB. Several reactants combine to form a single product. Next, decomposition looks like: AB--->A+B. a compound breaks down as a result of the chemical change. It is one reactant. Single looks like:A+BC--->AC+B. a compound breaks a part, and only ONE part combines with the other reactant-either an atom or a group of atoms. Lastly, a double looks like: AB+CD--->AD+CB. Both reactants break a part then they recombine into two new products. That's pretty much all the important stuff! Good luck on the quiz tomorrow everyone! :) homework below.

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Lesson 3, 4 and 5

In lesson 3, we covered a lot! Starting with physical change and chemical change. During a physical change, it is a change in matter in which a substance changes form but not identity. And a chemical Change is a change in matter that results in the formation of a new substance(s) with new properties. It is not always possible to distinguish between physical and chemical change based on observations alone. Ionic compounds do not dissolve in the same way as molecular solids. Something important to know is an ionic equation. Dissolving is considered a physical change (generally).

It looks like this: Ca2+ (aq) + Cl- (aq).

In lesson 4, if a gas is one of your products, the mass of the product will be less than the mass of then the reactants UNLESS you trap the gas! That's important to know! Also, on the entire planet there is essentially an unchanging number of atoms. With this, it is crucial to know matter cannot be created nor destroyed!! And mass and weight are DIFFERENT. Mass is the amount of "stuff" and weight is the gravitational pull. Individual atoms are conserved in chemical reactions and physical changes: the number of atoms of each element remains the same from start to finish!

In lesson 5, a balanced chemical equation is one that shows the true mathematical relationship between the reactants and the products in a chemical reaction. When balancing equations, start with atoms that only show up once on each side of the equation. Important! When balancing equations, you can only change the coefficients! That sums them up! Homework below :)

Homework:

This is for you Mrs.McDowell: :) sooo cute!

 

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New unit! Lesson 1 and 2:

Today we covered lessons 1 and 2. Lesson 1 covered toxins. Toxins are substances that interact with living organisms and cause harm. They can enter the body in a limited number of ways, they often react with water in the body. Toxins may be molecular, ionic, or metallic substances. We also learned a little bit how to write a interpretation of a chemical equation. For example:

NaCN(s)+HCL(aq)->NaCl(aq)+HCN(g) interpretation: solid sodium cyanide reacts with aqueous hydrochloric acid to produce aqueous sodium chloride and gaseous hydrogen cyanide.

In lesson 2, It was very short and we didn't cover much. Something important to know is that sometimes a change is described by more than one chemical equation. Also chemical equations allow you to track changes in matter on an atomic level. Also, there is some information that a chemical equation can't provide, and vise versa. That's all! Homework below :)

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Unit 3 Review!

Unit 3 covered a lot of weather! It started with learning how to read a weather map, and learning about warm fronts, cold fronts, precipitation, jet stream Ect. A warm front is warm air moving into the region. Because it is less dense than cold air, it moves up over the cold are and creates streaking clouds usually followed by precipitation. A cold air front overtakes cold air pushing it upward, due to the changing in altitudes and temperature the warm air quickly cools creating water vapor which turns into puffy clouds and precipitation. A jet stream is air moving swiftly from west to east across. Then we moved into how to measure rain. It is always measured by height and not volume. Moreover, we dove into equations. Starting with density, volume, mass, all the basics. Then we learned about thermometers and figuring out how to convert temperatures. F to C= 1.8(c)+32. And C to K= C+273. Something Important to know is kinetic theory of gases: - gas particles are constantly moving. - motion is random - speed is not always the same -particles move in straight lines - change directions when they hit each other or walls and lastly, the temperature changes the speeds. Higher temp= faster and excited molecules, lower temps: slower and not excited. Then we moved into the laws and determining when to use which ones. Charles Law= k=v/t, Boyles law: k=p times v, gay Lussac's law= k= p/t. Some important vocab words to know are sublimation, evaporation, condensation Ect. Chemists came up with a system of measurement to determine particles. 1mole= 6.022 times 10*23. And STP. Standard temperature and pressure. Temperature is 273K and 1.0atm. Then we went into another law, ideal gas law which is PV= nRT. Lastly, we went into hurricanes and a bit about global warming. Hurricanes are destructive storms characterized by strong winds and large amounts of rain. Good luck on the midterm everyone!!

Review:

 

 

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Lesson 19

Today and yesterday we covered lesson 19. Lesson 19 covers hurricanes. A hurricane is a destructive storm characterized by strong winds and large amounts of rainfall. Something important to know is tropical depressions can build to tropical storms, which can build to hurricanes. They are measured in 5 categories. 1 being the least intense and 5 being the most intense. Tropical storms form when a great deal of warm water evaporates into the atmosphere. Also, as the storm moves over areas of warmer water, evaporation increases. Water vapor density is related to temperature. As the temperature rises, the water vapor increases. Hurricanes form over the ocean in places where there is extreme warm, moist air. they also form around low pressure systems.Moreover, something important to know is that there is scientific edivdence that our earth is warming, called global warming, which causes climate change. Global warming may increase the frequency and intensity of hurricanes on the planet.

Lesson 18: Lesson 18 went over humidity. Humidity is the density of the water vapor in the air at any given time. Humidity is dependent on air temperature and pressure. The temperature at which water vapor condenses, indicates how much water vapor is in the air. Something important to know is that there is an upper limit to the amount of water vapor that can be present in the atmosphere at a given temperature. Humidity is sometimes expressed as relative humidity, which is the amount of water vapor in the air compared to the maximum amount of water vapor possible for a specific temperature, expressed as a percent. Lastly, water vapor density is affected by both air temperature and air pressure.

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Lesson 17

Today we went over lesson 17 and some of lesson 19. In lesson 17, it mostly covered the ideal gas law. The ideal gas law states that PV=nRT, where R, the universal gas constant, is equivalent to the proportionality constant, k, for this equation. R=PV/nT. The ideal gas law relates to pressure, temperature and volume. Something important to know is that R does not change unless the units change. We also talked a little bit more about moles. The number of moles can be converted to the total number of gas molecules by X by 602 sextillion. We also did a lab which measure the volume of one breath of air. Homework below!

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Lessons 15 and 16

Today we covered lesson 15 and lesson 16. Starting with lesson 15, the most important thing to understand is number density. Number Density is the number of gas particles per unit volume. It can be written in the equation density= n/V. Something that goes along with number density is gas pressure. The gas pressure increases as the number of gas molecules per unit of volume increases. P=k(n/V). Moreover, air pressure can be measured by determining the difference in height of the liquid. My homework may help explain all of that better!

In lesson 16, we first started with understanding a mole! A mole is a unit of measurement that chemists came up with in order to more easily measure gas particles. It is very difficult to measure each particle individually. Therefore, Avogadro's Law and the mole help simplify! One mole= 602,200,000,000,000,000,000,000 OR 6,022 times 10 to the 23. Going along with Avogadro's law, STP comes into play. It is the standard temperature and pressure (1atm and 273K). Equal volumes of gases contain equal numbers of gas particles if the temperature and pressure and the same (STP). Lastly! 1 mole= 22.4L at STP.

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Lessons 13 and 14

In lesson 13, we covered the combined gas law. This law is the relationship among the pressure, temperature, and volume of a gas. It's formula us k=PV devised by T. OR P1V1 decided by T1= P2V2 decided by T2. Something important to know is that air temperature and air pressure both decrease with increases in altitude. For weather balloons, gas pressure has a greater effect on gas volume than does gas temperature. That covers most of lesson 13!

In lesson 14, we did a lab and talked more about clouds. Gay Lussac's Law also tells us that when the pressure inside the bottle increased, the temperature also must increase. Clouds form when water vapor in the atmosphere changes phases and forms water droplets. Clouds can also only form when there is enough water vapor present. Clouds form when both air pressure and temperature are low. Low air pressure are associated with fronts, storms, clouds, and precipitation. Warm air pressure are associated with clear skies. Something else important to know is that warm air rises because it is less dense than cold air.

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Lesson 12

We covered lesson 12, and began the activity for lesson 13. In lesson 12, we started with the gas laws. The gas laws calculate new values for gas temperature,pressure, and volume when two of these conditions change. Understanding the laws are key, Charles law: V= kT, k= V/T. Pressure and amount of gas DO NOT change. Gay-Lussac's Law: P=kT, k= P/T. Volume and amount of gas DO NOT change. Boyle's Law: P=k times (1/V), k=PV. Temperature and amount of gas DO NOT change. Lastly, Charles Law and Gay Lussac's law are proportional relationships. Understanding these laws and when to use them is what we went over and practiced. Homework below :) hope everyone is having a great homecoming week!

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Lesson 11

Today we covered different laws and gas. During the demonstration, the gas inside the flask cools the pressure of the gas inside the flask decreases. Gays-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, and if the temperature is expressed in kelvin. Also something important to know is that in a flexible container, changing the temperature or pressure causes the volume to change. Rigid container increases the temperature causes the pressure to increase. Gas can enter or escape the container. That covers the basics! Homework below might help :) if anyone gets number 3... I don't! So some help would be appreciated :)

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Lessons 8,9 and 10

Starting with lesson 8, we learned about sublimation. Sublimation is the phase change from a solid to a gas. Remembering back to the lab, when we saw the "fog" around the dry ice, it is actually tiny droplets of water. Something important to know is that the gaseous co2 can occupy is dramatically larger than the space that a solid co2 occupies. Moreover! Evaporation (in case you didn't know ;)) is the phase change from a liquid to a gas. An important equation you'll need to know is %error=experimental value-accepted value devised by an accepted value times 100. A fun fact to know closing up lesson 8 is that molecules of gas are about 1000 times more dispersed (less dense) than the molecules of a solid.

Lesson 9 covered air pressure! We watched some demonstrations showing air pressure. For example, if you were to try to blow up a ballon while it was in a bottle, due to the air pressure in the bottle, it is impossible. All the demonstrations were really fascinating! In case you were wondering, air pressure is the force per unit area exerted on objects as a result of gas molecules colliding with those objects. Pressure is similar, but its important to know the definition. Pressure is the force applied over a specific area. Force per unit area. Gas pressure is caused by gas molecules striking objects or the walls of the container. A mixture of gases that surrounds you at all times is called the atmosphere! Along with that come atmospheric pressure which is important. It is air pressure that is always present on earth as a result of air molecules colliding with the surfaces of objects on the planet. Lesson 9 closes up with knowing that at sea level, and 25° C, there is a 14.7 in/in2. This is referred to as 1 atmosphere of pressure or 1 amu.

Lesson 10 covers Boyles law. If you understand that, than lesson 10 is done! Boyles law is the pressure of a given amount of gas is inversely proportional to its volume if the temperature and amount of gas are not changed. When volume of a gas decreases, it's pressure increases. The mathematical relationship between pressure and volume is P=k/V or PV=k.

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