Saturday, September 26, 2015
Friday, September 25, 2015
Chapter 3 Lesson 1
Chapter 3:
Solve each problem and express the answer in scientific notation
a. (6.6 ❌ 10^-8) + (5 ❌10^-9)
6.6E-8+5E-9=7.1E-8
6.6❌10^-8+.5❌10^-8... 6.6+.5= 7.1 ❌10^-8
Answer: 7.1E-8
b. (9.4 ❌10^-2) - (2.1 ❌ 10^-2)
9.4E-2-2.1E-2= .073
9.4-2.1=7.3❌10^-2 or .073
Answer: 7.3E-2
2. Calculate the following and write your answer in scientific notation:
6.6❌10^6➗
(8.8❌10^-2) ❌ (2.5❌10^3)
6.6❌10^6=6.6E6
(8.8E-2) ❌ (2.5E3)= 220 or 2.2❌10^2
6.6❌10^6 ➗ 2.2❌10^2= 30000 or. 3E4
Answer from trying it by hand: 3E4
From calculador: 1.9E11
3. The student measures the depth of a swimming pool to be 2.04 meters at its deepest end. The accepted value is 2.0 meters. What's the students percent error. 2.04-2.0➗2.0❌100=.2. The percentage of error is .2%
13. Accuracy is a measure of how close a measurement comes to the actual or true value of whatever is measured. Precision is a measure of how close a series of measurements are to one another, irrespective of the actual value. You can measure accuracy by comparing it to the correct answer. Precision can be measured by comparing it to two or more other related measurements.
15. Calculate A technician experimentally determined the boiling point of octane to be 124.1ºC. The actual boiling point of octane is 125.7ºC. Calculate the error and the percent error. 124.1-125.7➗125.7❌100= 1.273 rounded. The percentage of error rounded is 1.273%
17. Calculate Solve the following and express each answer in scientific notation and to the correct number of significant figures.
a. (5.3 ❌ 10^4) + (1.3❌10^4)
6.6❌10^4=66000
Answer+ 6.6E4
b. (7.2 ❌ 10^-4) ➗ (1.8❌10^3)
7.2➗1.8❌10^-7= 4E-7
Answer: 4E-7
c. 10^4 ❌ 10^−3 ❌ 10^6
10^4 ❌ 10^−3 ❌ 10^6= 1E10
Answer: 1E10
d. (9.12 ❌ 10^−1) - (4.7 ❌ 10^−2)
(9.12E-1)-(4.7E-2)= .865
9.12-.47=8.65^-1
Answer: 8.65E-1
e. (5.4❌ 10^4) ❌ (3.5 ❌ 10^9)
(5.4E4)❌(3.5E9)= 1.89E14
18.9❌10^13=18.9 move decimal and round
Answer: 1.9E14
Monday, September 21, 2015
Lesson 3,4
32. A chemical change affects the composition of matter because once a chemical change takes place the composition of the matter is changed, if the composition is not changed at all it is not a chemical change.
33. Four possible clues that a chemical change has taken place are transfer of energy, change in color, the production of gas, or formation of a precipitate which is a solid that forms and solids out of a liquid.
34. Compare In a chemical reaction, the mass of the products is always equal to he mass of the reactants, for example the mass of a log will be equal to the mass of all the snake and ash made by burning the log.
35. The main difference between physical changes and chemical changes is a physical change does not change the composition of the matter, it just changes forms. In a chemical change the composition of the product is changed.
36. Classify the following changes as physical or chemical changes.
a. Water boiling would be a physical change.
b. Table salt dissolves in water would be a physical change.
c. Milk turning sour would be a chemical change.
d. A metal rusting would be a chemical change.
41. Two physical properties that could be used to distinguish between water and ethanol is that water boils at 100 degrees centigrade and ethanol boils at 78.3 degrees centigrade. Also ethanol freezes at -174.6 degrees Fahrenheit and water freezes at 32 degrees Fahrenheit.
42. One physical property that could not be used to distinguish chlorine from oxygen is that both chlorine and oxygen are gases at room temperature.
43. What is the physical state of each of these materials at room temperature?
a. Gold's physical state at room temperature is solid
b. Gasoline's physical state at room temperature is liquid
c. Oxygen's physical state at room temperature is gas
d. Neon's physical state at room temperature is gas
e. Olive oil's physical state at room temperature is liquid
f. Sulfur's physical state at room temperature is solid
g. Mercury's physical state at room temperature is liquid
44. Fingernail-polish remover (mostly acetone) is a liquid at room temperature. Acetone in the gaseous state is a vapor because a vapor is the gaseous state of something that is normally a solid or a liquid and nail polish remover is normally a liquid. A gas is something that is usually always a gas.
50. Classify each of the following as a homogeneous or heterogeneous mixture.
a. Chocolate-chip ice cream would be classified as a heterogeneous mixture
b. Green ink would be classified as a homogeneous mixture
c. Cake batter would be classified as a heterogeneous mixture
d. Cooking oil would be classified as a homogeneous mixture
e. Granite rock would be classified as a heterogeneous mixture
f. Salt water would be classified as a heterogeneous mixture
g. Paint would be classified as a homogeneous mixture
h. A silver ring would be classified as a homogeneous mixture
54. Describe the relationship between the three items in each of the following groups. Identify each item as an element, compound, or mixture.
a. Hydrogen, oxygen, are both elements and water is a compound made from the elements hydrogen and oxygen
b. Nitrogen and oxygen, are elements and air is a mixture of both nitrogen and oxygen.
c. Sodium and chlorine are both elements and table salt is a compound of both sodium and chlorine
d. Carbon is an element and water is a compound and together they can make the mixture of table sugar.
60. Classify each of the following as a physical or chemical change. For any chemical change, list at least one clue to support your answer.
a. A copper wire being bent is a physical change because the chemical makeup is not being changed, only the physical appearance.
b. Charcoal burns in a grill is a chemical because the gas bonds to other elements to form a new substance, it is also irreversible.
c. Bread dough rises when yeast is added is a chemical change because the substance is changed and can't be reversed. It may be changed physical also but it's a result of a physical change.
d. Sugar dissolves in water is a physical change because the compounds are not bonding to creat new substances, they are just mixing. Dissolving is not a chemical change.
63. Ethanol is a colorless liquid at −30°C
64. Neon is a colorless gas at 60°C
65. Sulfur is a solid at 7°C
66. As the temperature rises sulfur is natural solid will melt before mercury boils. Sulfur melts at 115 degrees C. and Mercury boils at 357 degrees C. However, all the substances on the chart will melt before Mercury boils, all melting under 357 degrees C.
Saturday, September 19, 2015
Thursday, September 17, 2015
Lesson 1, 2, and 3. Questions 1-8, 12-15, 20-29
Page 80:
1. All samples of a given substance have the same intensive properties because intensive properties look at the type of matter not how much of it there is. So all substances have the same intensive properties even if the amount of the substance changes.
2. Three states of matter:
1. Solid
2. Liquid
3. Gas
3. Two categories used to classify physical changes are reversible and irreversible. Boil, freeze, melt, and condense are reversible. Break, split, grind, cut, and, crush are irreversible.
4. Two categories used to classify properties of matter are extensive properties and intensive properties. An intensive property is the type of matter and extensive properties are the amount of matter.
5. In the Physical Properties of Some Substances table you can most easily distinguish sodium chloride from the other solids by its melting point and boiling point. Many substances are solid and white but not all solid white substances melt at 801 degrees C or boil at 1413 degrees C.
6. Liquids and gases alike because they both move freely and they are both fluid, meaning they take the form of what ever they are inside of. Liquids and solids are different because molecules in solids are more condensed than molecules in liquids because solids have definite shapes and volumes
7. The freezing of mercury is a reversible physical change because the Mercury can be melted until it is back to its original state. This is a physical change because the chemical make up stays the same even though it's state of matter may have changed.
8. Samples of platinum and copper can have the same extensive properties but not the same intensive properties because platinum and copper may have the same amount of mass per square unit, but their mass is made up of different things.
Page 87:
12. Mixtures are classified by heterogeneous- separate and homogenous- together.
13. The types of properties that can be used to separate mixtures are filtration and distillation. Filtration a solid from a liquid in a heterogeneous mixture. Distillation can separate water from other components in tap water.
14. The term phase is used to describe any part of a sample with uniform composition. It relates to homogeneous and heterogeneous mixtures because a homogeneous mixture has only one phase because it is all one thing, a heterogeneous mixture has 2 or more phases because they are not "mixed" together.
15. Classify each of the following as a homogeneous or heterogeneous mixture.
a. food coloring: homogeneous
b. ice cubes in liquid water: heterogeneous until ice melts
c. mouthwash: homogeneous
d. mashed, unpeeled potatoes: heterogeneous
Page 95:
20. If two clear liquids, A and B sit out and evaporate and there is a white solid still left in container B and nothing in container A I can infer that container B had a compound in it that separated when it evaporated and container A might have had an element that evaporated all together.
21. If a liquid is left out to evaporate and after three days there is a solid left in the container I can infer that the liquid was not an element because elements can not separate. This either means it was a compound that separated into elements or a mixture separated into compounds.
Page 100:
22. A compound different from an element be because a compound can be broken down into a smaller form: an element. An element can not be broken down any smaller.
23. You can distinguish a substance from a mixture because a substance has a fixed amount of materials and a mixture has variety of materials.
24. Chemical symbols are used to show elements and chemical formulas are used to show compounds.
25. The periodic table is such a useful tool because it makes it easier to compare elements and what they are. You can compare elements mass and atomic number.
26. Two methods that can be used to break down compounds into simpler substances are heat and electricity. Heating does not break down water. An electric current will, however, break down water into hydrogen and oxygen, but from there it can not be broken down any smaller because hydrogen and oxygen are element.
27. Classify each of these samples of matter as an element, a compound, or a mixture.
a. table sugar: compound
b. tap water: mixture. Only pure H2O would be a compound
c. cough syrup: mixture
d. nitrogen: element
28. Write the chemical symbol for each of the following elements:
a. lead: Pb
b. oxygen: O
c. silver: Ag
d. sodium: Na
e. hydrogen: H
f. aluminum: Al
29. Name the chemical elements represented by the following symbols
a. C: Carbon
b. Ca: Calcium
c. K: Potassium
d. Au: Gold
e. Fe: Iron
f. Cu: Copper
Wednesday, September 16, 2015
I don't know why it's blurry! Also we didn't finish the video!
Tuesday, September 15, 2015
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