Chapter 3 - Matter and energy Flashcards
Classify each of the following pure substances as an element or a compound.
a) a silicon (Si) chip
b) hydrogen peroxide (H2 O2)
c) oxygen gas (O2)
d) rust (Fe2 O2)
e) Methane CH4 (natural gas)
a) a silicon (Si) chip {ELEMENT}
b) hydrogen peroxide (H2 O2) {__COMPOUND__}
c) oxygen gas (O2) {ELEMENT}
d) rest (Fe2 O2) {__COMPOUND__}
e) Methane (natural gas) {__COMPOUND__}
Pure substances are made up of one type of atom or molecule. Elements are composed of only one type of atom and have one chemical symbol in their formulas, whereas compounds consist of atoms of two or more elements chemically bonded together and have multiple element symbols in their chemical formulas.
Classify each of the following as a homogenous or heterogeneous mixture.
a) Herbal tea
b) Hot fudge sundae
c) vegetable oil
a) Herbal tea {__HOMOGENOUS__}
b) Hot fudge sundae {__HETEROGENOUS__}
c) vegetable oil {__HOMOGENOUS__}
Classify each of the following as an element, a compound, or a mixture.
a) Acetic acid (CH3COOH) in apple cider vinegar
b) an oil spill in the ocean
c) xenon gas in lights
a) Acetic acid (CH3COOH) in apple cider vinegar {__compound __}
b) an oil spill in the ocean {__ mixture __}
c) xenon gas in lights {__element __}
All attempts used; correct answer displayed
You sorted 1 out of 3 items incorrectly. Recall that an element contains only one single type of atom, as found in the periodic table, while a compound is made up of two or more atoms. A mixture contains two or more different substances, such as a mixture of compounds or atoms. If the substance is a single species that contains two or more elements that you can look up in the periodic table, it is a compound.
The element xenon has the chemical formula Xe and can be found on the periodic table. Elements are the simplest type of a pure substance. The oil and water in the ocean spill are not chemically bonded together and can be physically separated, using a filter. Therefore, they form a mixture. The atoms of carbon, hydrogen, and oxygen in acetic acid are chemically bonded together to form the compound acetic acid.
No, vinegar is not a compound. A compound is formed when two separate and different materials (element, molecule, or even another compound) form a bond to each other.
Oil is a complex mixture of molecular compounds. A molecule is the smallest unit of a substance that retains the substance’s characteristics. Molecules, in turn, are composed of atoms.
Xenon (Xe), chemical element, a heavy and extremely rare gas of Group 18 (noble gases) of the periodic table. It was the first noble gas found to form true chemical compounds. More than 4.5 times heavier than air, xenon is colourless, odourless, and tasteless.
Iron rusting is a Physical or Chemical change?
Chemical change
Grinding coffee beans is Physical or Chemical change?
Physical change
digesting a cheeseburger baking a cake burning coal converting water to hydrogen and oxygen are all examples of a Physical or Chemical change?
Chemical change
The physical state(s) present when a substance is melting is (are)
Solid + liquid
When a solid is converted directly to a gas, the change of state is called
sublimation
What is 68 ∘F in degrees Celsius?
Using the equation that relates a Fahrenheit temperature and its corresponding Celsius temperature, 32 is subtracted from 68 ∘C . Then that result is divided by 1.8.
TC=(TF−32)/1.8
TC=68∘C/1.8
TC=20.∘C
What is 68 ∘F in kelvins?
After converting the Fahrenheit temperature to Celsius, as done in Part A, the equation that relates a Celsius temperature and its corresponding Kelvin temperature is used:
TK=TC+273
=20.∘C+273
=293 K
Using the energy values for foods (see the table), determine each of the following (round off the answers in kilocalories or kilojoules to the tens place):
Food Type kcal/g kJ/g
Carbohydrate 4 17
Fat 9 38
Protein 4 17
the total kilojoules for one cup of orange juice that contains 27 g of carbohydrate, no fat, and 2 g of protein
Express your answer to two significant figures and include the appropriate units.
carb=17kJ/g
fat=9
27g x 17kJ/g = 459kJ
2g x 17kJ=34kJ
459kJ+34kJ= 493kJ
2 sig figs = 49x10 to the 1 kJ or 490kJ
Using the energy values for foods (see the table), determine each of the following (round off the answers in kilocalories or kilojoules to the tens place):
Food Type kcal/g kJ/g
Carbohydrate 4 17
Fat 9 38
Protein 4 17
the grams of carbohydrate in one apple if the apple has no fat and no protein and provides 67 kcal of energy
Express your answer to two significant figures and include the appropriate units.
so you can use dimensional analysis,
you need a value in grams, and you have “kcal/g” and “kcal”.
You need to cancel out “kcal” and have “g” at the top (numerator).
kcalkcal/g=kcalkcal∗g=g
so divide the energy by the values given in the table.
Mass of apple =67kcal4kcal/g=16.75 g
2 sigs= 17g
Using the energy values for foods (see the table), determine each of the following (round off the answers in kilocalories or kilojoules to the tens place):
Food Type kcal/g kJ/g
Carbohydrate 4 17
Fat 9 38
Protein 4 17
the kilocalories in one tablespoon of vegetable oil, which contains 15 g of fat and no carbohydrate or protein
140kcal
Using the energy values for foods (see the table), determine each of the following (round off the answers in kilocalories or kilojoules to the tens place):
Food Type kcal/g kJ/g
Carbohydrate 4 17
Fat 9 38
Protein 4 17
the grams of fat in one avocado that has 385 kcal, 15 g of carbohydrate, and 1 g of protein
36g
What is 53 ∘F in degrees Celsius?
Using the equation that relates a Fahrenheit temperature and its corresponding Celsius temperature, 32 is subtracted from 53 ∘C . Then that result is divided by 1.8.
Tc=(TF−32)1.8
=53∘C1.8
=12∘C
What is 53 ∘F in kelvins?
After converting the Fahrenheit temperature to Celsius, as done in Part A, the equation that relates a Celsius temperature and its corresponding Kelvin temperature is used:
TK =TC+273
=12∘C+273
=285K
Using the energy values for foods (see the table), determine each of the following (round off the answers in kilocalories or kilojoules to the tens place):
Food Type kcal/g kJ/g
Carbohydrate 4 17
Fat 9 38
Protein 4 17
the total kilojoules for one cup of orange juice that contains 28 g of carbohydrate, no fat, and 3 g of protein
carb=17kJ/g
fat=9
28g x 17kJ/g = 476kJ
3g x 17kJ=51kJ
476kJ+51kJ= 527kJ
2 sig figs = 530 kJ
Using the energy values for foods (see the table), determine each of the following (round off the answers in kilocalories or kilojoules to the tens place):
Food Type kcal/g kJ/g
Carbohydrate 4 17
Fat 9 38
Protein 4 17
the grams of carbohydrate in one apple if the apple has no fat and no protein and provides 61 kcal of energy
so you can use dimensional analysis,
you need a value in grams, and you have “kcal/g” and “kcal”.
You need to cancel out “kcal” and have “g” at the top (numerator).
kcalkcal/g=kcalkcal∗g=g
so divide the energy by the values given in the table.
Mass of apple =61kcal4kcal/g=15.25 g
2sigs=15g
Using the energy values for foods (see the table), determine each of the following (round off the answers in kilocalories or kilojoules to the tens place):
Food Type kcal/g kJ/g
Carbohydrate 4 17
Fat 9 38
Protein 4 17
the kilocalories in one tablespoon of vegetable oil, which contains 19 g of fat and no carbohydrate or protein
170kcal
Using the energy values for foods (see the table), determine each of the following (round off the answers in kilocalories or kilojoules to the tens place):
Food Type kcal/g kJ/g
Carbohydrate 4 17
Fat 9 38
Protein 4 17
the grams of fat in one avocado that has 455 kcal, 17 g of carbohydrate, and 4 g of protein
15x4 carb=60
1x4 protein=4
455-64=391
391/9 fat=43.4
round to the nearest tenths = 41g
Correct answer is shown. Your answer 40g was either rounded differently or used a different number of significant figures than required for this part.
41g
Classify each of the following as an element, a compound, or a mixture.
a) xenon gas in lights
b) sodium hypochlorite (NaOCl) in bleach
c) a salad dressing in oil and vinegar
a) xenon gas in lights -element
b) sodium hypochlorite (NaOCl) in bleach- compound
c) a salad dressing in oil and vinegar - mixture
Matter
- is the material that makes up all things
* is anything that has mass and occupies space
Matter is classified according to its composition:
Pure substance
Mixtures
Pure substances
have a fixed or definite composition.
Mixtures
contain two or more different substances that are physically mixed but not chemically combined.
•two or more substances in different proportions •substances that can be separated by physical methods
A pure substance is classified as -
Elements
Compounds
Elements
are pure substances that contain only one type of material, such as
•copper, Cu
•lead, Pb
•aluminum, Al
The element copper consists of copper atoms.
Compound
A compound contains two or more elements in a definite ratio, such as • hydrogen peroxide (H2O2) • table salt (NaCl) • sugar (C12H22O11) • water (H2O)
Homogeneous Mixtures
In a homogeneous mixture,
•the composition is uniform throughout
•the different parts of the mixture are not visible
Familiar examples of homogeneous mixtures are air, which contains oxygen and nitrogen gases, and seawater, a solution
of salt and water.
These are called solutions such as sugar solution
Brass is a homogeneous mixture of copper and zinc atoms.
Heterogeneous Mixtures
In a heterogeneous mixture,
•the composition varies from one part of the mixture to another
•the different parts of the mixture are visible
these are called suspension and colloid such as soap
Identify each of the following as a pure substance or a mixture: A. pasta and tomato sauce B. aluminum foil C. helium D. air
A. pasta and tomato sauce - mixture
B. aluminum foil - pure substance
C. helium - pure substance
D. air - mixture
Identify each of the following as a homogeneous or heterogeneous mixture: A. hot fudge sundae B. shampoo C. sugar water D. peach pie
A. hot fudge sundae - heterogeneous mixture
B. shampoo - homogeneous mixture
C. sugar water - homogeneous mixture
D. peach pie - heterogeneous mixture
Physical Change
A physical change occurs in a substance if there is
•a change in the state
•a change in the physical shape
•no change in the identity and composition of the substance
Chemical Change
During a chemical change, a new substance forms that has
•a new composition
•new chemical properties
•new physical properties
Sugar caramelizing at a high temperature is an example of a chemical change.
Classify each of the following changes as physical or chemical: A. burning a candle B. ice melting on the street C. toasting a marshmallow D. cutting a pizza E. iron rusting in an old car
A. burning a candle - chemical
B. ice melting on the street - physical
C. toasting a marshmallow - chemical
D. cutting a pizza - physical
E. iron rusting in an old car - chemical
Temperature
Temperature
•is a measure of how hot or cold an object is compared to another object
•indicates the heat flow from the object with a higher temperature to the object with a lower temperature
•is measured using a thermometer
•A comparison of the Fahrenheit, Celsius, and Kelvin temperature scales
Celsius to Fahrenheit Conversion
Multiply the °C temperature by 1.8. Add 32 to this number. This is the answer in °F.
°F = (°C × 9/5) + 32
Fahrenheit to Celsius conversion
°C = (°F − 32) x 5/9
Example °C to °F Conversion
For example, to convert 26°C to °F (the temperature of a warm day):
°F = (°C × 9/5) + 32
°F = (26 × 9/5) + 32
°F = (46.8) + 32
°F = 78.8° F
A person with hypothermia has a body temperature of 34.8 °C. What is that temperature in degrees Fahrenheit?
TF = 1.8TC + 32
TF = 1.8(34.8) + 32
TF = 62.6 + 32 = 94.6 °F
Answer to the tenths place.
On a cold winter day, the temperature is –15 °F. What is that temperature in degrees Celsius? A. −85 °C B. −47 °C C. −42 °C D. −26 °C
TC = (–15 − 32) / 1.8
TC = –47 /1.8 = −26 °C
Answer is D.
Energy
In countries other than the United States, energy is shown in kilojoules (kJ).
1 Cal = 1000 calories
1 Cal = 1 kcal
A cup of whole milk contains 13 g of carbohydrate, 9.0 g of fat, and 9.0 g of protein. How many kilocalories does a cup of milk contain? (Round the final answer to the tens place.)
A. 50 kcal
B. 80 kcal
C. 170 kcal
13 g carbohydrate× 4 kcal/g= 52 kcal
- 0 g fat × 9 kcal/g = 81 kcal
- 0 g protein × 4 kcal/g = 36 kcal
Total energy = 52 kcal + 81 kcal + 36 kcal = 169 kcal
Answer is C. 170kcal
Classify each of the following as a pure substance (element or compound) or a mixture
(homogeneous or heterogeneous):
a. copper in wire
b. a chocolate-chip cookie
c. nitrox, a combination of oxygen and nitrogen used to fill scuba tank
SOLUTION
a. Copper is an element, which is a pure substance.
b. A chocolate-chip cookie does not have a uniform composition, which makes it a heterogeneous mixture.
c. The gases oxygen and nitrogen have a uniform composition in nitrox, which makes it a
homogeneous mixture
A salad dressing is prepared with oil, vinegar, and chunks of blue cheese. Is this a homogeneous or heterogeneous mixture
heterogeneous mixture
molecules
is the smallest piece of a compound that is still a compound.
How to convert Celsius to Kelvin?
K=C+273
40 degree Celsius to Kelvin?
K=C+273
K=40+273
K=313
313K
How to convert Kelvin to Celsius?
C=K-273
313K to Celsius?
C=K-273
C=313-273
C=40
40C
How to convert Celsius to Fahrenheit?
F=1.8C+32
12 degree Celsius to Fahrenheit?
F=(1.8x12)+32
F=21.6+32
F=53.6
53.6 degrees F
50 degrees Celsius to F
F=(1.8x50)+32
F=90+32
F=122
122 degrees F
How to convert Fahrenheit to Celsius?
F-32=1.8C
80 degree F to Celsius
F-32=1.8C 80-32=1.8C 48=1.8C 48/1.8=C 26.6=C 26.6 degrees Celsius
Difficult temp conversion:
300K to F
first: K to C
then C to F
K to C
300 -273=C
27=C
then C to F
F=(1.8x27)+32
F=48.6+32
F=80.6
Convert 100 degree F to Kelvin
F to C then C to K 1.8C=F-32 1.8C=100-32 1.8C=68 c=68/1.8 C=37.7
K=273+37.7
K=310.7
