Midterm Exam Flashcards by Ashleigh Alexander

(Vocab)
Scientific Method

Organized approach to solve a problem

How well did you know this?

Not at all

Perfectly

What are the steps of the scientific method and explain?

Observe - Define the problem (use 5 senses)

Hypothesis - Reasonable explanations for what was observed (educated guess)

Experiments - Test each hypothesis in order to prove/disapprove them

Analysis - Compares the results from the experiments to the original hypothesis

Conclusion (Theory) - A hypothesis supported by experimental evidence

How well did you know this?

Not at all

Perfectly

(Vocab)
Law

Used to describe a natural phenomenon which has been tested over a long period of time

How well did you know this?

Not at all

Perfectly

(Vocab)
Theory

A hypothesis supported by experimental evidence

How well did you know this?

Not at all

Perfectly

(Vocab)
Chemistry

The study of matter + the changes it undergoes

How well did you know this?

Not at all

Perfectly

What is the difference between an element and a compound?

Elements = made up of one atom
compounds = made up of 2 or more diff. elements (multiple atoms)

How well did you know this?

Not at all

Perfectly

Give examples of an element.

Hydrogen, Helium, Carbon etc. (anything on the Periodic Table)

How well did you know this?

Not at all

Perfectly

Give examples of a compound.

CO2 (carbon dioxide), NO2 (nitrogen dioxide)
(formed when elements chemically combine)

How well did you know this?

Not at all

Perfectly

(Vocab)
Homogeneous mixture + examples

Has a uniform composition (parts of the mixture + cannot be picked out)
Ex: milk, sugar

How well did you know this?

Not at all

Perfectly

(Vocab)
Heterogeneous mixture + examples

Doesn’t have a uniform composition (Parts of the mixture can be physically seen + picked out)
Ex: cereal, salad, pizza

How well did you know this?

Not at all

Perfectly

(Vocab)
Chemical changes + examples

One or more substances react to form new substances w/ diff. chemical + physical properties (The beginning substances w/ diff. than the ending substances)
Ex: rusting, burning, decaying

How well did you know this?

Not at all

Perfectly

(Vocab)
Physical changes + examples

Changes in appearance w/o changing composition
Ex: cutting, breaking, freezing, boiling, melting

How well did you know this?

Not at all

Perfectly

(Vocab)
Physical Properties + examples

Properties that can be measured or observed w/o changing the identity (or composition) of a substance
Ex: color, odor, texture, taste

How well did you know this?

Not at all

Perfectly

(Vocab)
Chemical Properties + examples

Properties that indicate how a substance reacts w/ other substances.
Ex: flammable, combustible, burnable

How well did you know this?

Not at all

Perfectly

(Vocab)
Law of Conservation of Matter/Mass

In any chemical or physical change, matter cannot be created or destroyed (mass of reactants = mass of products)

How well did you know this?

Not at all

Perfectly

Explain the difference between accuracy and precision.

Accuracy = How close a measurement is to the true or accepted value
Precision = How close multiple measurements are to each other

How well did you know this?

Not at all

Perfectly

Write out 3.5 x 10^-5 in long form.

0.000035

How well did you know this?

Not at all

Perfectly

Write out 7,123 in scientific notation

7.123 x 10^3

How well did you know this?

Not at all

Perfectly

Write out 0.000000081 in scientific notation

8.1 x 10^-8

How well did you know this?

Not at all

Perfectly

Write out 8 x 10^8 in long form.

800,000,000

How well did you know this?

Not at all

Perfectly

Answer (6 x 10^-8) x (4x10^-4) in proper scientific notation.

2.4 x 10^-11

How well did you know this?

Not at all

Perfectly

Write out 453,000 in scientific notation

4.53 x 10^5

How well did you know this?

Not at all

Perfectly

Write out 0.000157 in scientific notation

1.57 x 10^-4

How well did you know this?

Not at all

Perfectly

Solve: 30,000 x 0.0004 in scientific form

1.2 x 10^1

How well did you know this?

Not at all

Perfectly

Write out 2 x 10^3 in long form.

2000

Solve: (3 x 10^-8) x (7 x 10^6) in scientific notation

2.1 x 10^-1

Write out 0.0029 in scientific notation.

2.9 x 10^-3

Solve: 37,000 x 7,000 in scientific notation

2.59 x 10^8

Write out 41,000 in scientific notation.

4.1 x 10^4

Write out 60,007,000 in scientific notation.

6.0007 x 10^7

List the rules for Significant Figures

1) All non-zero digits are significant 2) Leading zeros are never significant (zeros to the left) 3) Captive zeros are always significant (zeros in the middle) 4) Trailing zeros are sometimes significant (zeros at the end) - they are sig. if the # contains a decimal point - they aren’t sig. if # does NOT contain a decimal point

What is the rule for Addition and Subtraction when solving an equation with sig. figs.?

the answer is rounded to the same # of decimal places as the # used in the calculation with the least decimal places. Ex #1: 7.12 - 1.345 = 5.775 = 5.78 (7.12 has the least number of decimal places in the equation so we would round our answer 5.775 to have the same amt of decimal places. This would make the answer 5.78, which is also rounded to the nearest hundredth, DONT FORGET TO ROUND) Ex #2: 5.7 + 2.11 = 7.81 = 7.8

What is the rule for Multiplication and Division when solving an equation with sig. figs.?

the answer is rounded to the same # of sig. figs. as the # used in the calculation with the least sig. figs. Ex #1: 17.85/2.13 = 8.38028 = 8.38 (You divide the 2 #’s and get that long number but since 2.13 is the # with the least sig. figs. you round your answer to get the same amt of sig. figs., which is 3, this will lead you to get the answer 8.38) Ex #2: 0.0561 x 0.030 = 0.001683 = 0.0017 (rounded)

What is Dimensional Analysis?

A method used to convert units

Solve using Dimensional Analysis, How many seconds are in 1.50 weeks?

907 s

how many sig. figs. are in the number 0.02?

(Vocab) Matter

Anything that has mass + volume (everything)

How many g are equal to 345.7 mg?

0.3457

How many Micrograms (μg), Microliters (μL), and Micrometers (μm) are in grams (g), liters (L), and meters (m)?

10^-6μg = 1g 10^-6μL = 1L 10^-6μm = 1m

(Vocab) Mass

The amount of matter in an object

how many sig. figs. are in the number 0.020?

Solve using Dimensional Analysis, how many feet are equal to 54.7 inches?

4.56 ft

How many Kg are equal to 45,000 mg?

0.045 kg

How many Milligrams (mg), Milliliters (mL), and Millimeters (mm) are in grams (g), liters (L), and meters (m)?

1000mg = 1g 1000mL = 1L 1000mm = 1m

Answer the equation with the correct amt of sig. figs. 16.590/1.8 = ?

9.2

how many sig. figs. are in the number 2.0x10^-3?

How many mins are in an hour?

60 mins.

How much feet are in a mile?

5280 feet

Mount Everest is approximately 8,000 meters high. How many miles high is Mount Everest?

5 miles

What is the symbol and meaning for the prefix micro?

Symbol: μ Meaning: millionth (10 ^-6)

Answer the equation with the correct amt of sig. figs. 3.085 + 2.77448 = ?

1.112

Answer the equation with the correct amt of sig. figs. 3.42 + 8.132 = ?

11.55

How many hours are in a day?

24 hours

how many sig. figs. are in the number 2,002?

Answer the equation with the correct amt of sig. figs. 1.2 x 1.3 = ?

1.6

Answer the equation with the correct amt of sig. figs. 32.88/4.38 = ?

7.51

A homerun in a baseball game was measured at 450 ft. How many meters is this equal to?

14 meters

How many ounces are in a pound?

16 ounces

What is the symbol and meaning for the prefix Kilo?

Symbol: K Meaning: thousand

Answer the equation with the correct amt of sig. figs. 2.16 x 1.8 = ?

3.9

how many sig. figs. are in the number 20,000?

Answer the equation with the correct amt of sig. figs. 4.55 + 3.45 = ?

8.00

What is the symbol and meaning for the prefix Milli?

Symbol: m Meaning: thousandth

how many sig. figs. are in the number 20,020?

A chemistry student has a weight of 155 lbs. What is the student’s weight in grams? (1oz = 28.34 g)

70,300 g

What is the symbol and meaning for the prefix Centi?

Symbol: c Meaning: hundredth (0.01)

Answer the equation with the correct amt of sig. figs. 4.3324 x 1.2 = ?

5.2

How many Decigrams (dg), Deciliters (dL), and Decimeters (dm) are in grams (g), liters (L), and meters (m)?

10dg = 1g 10dL = 1L 10dm = 1m

What is the symbol and meaning for the prefix Deci?

Symbol: d Meaning: tenth (0.1)

how many sig. figs. are in the number 1.09x10^4?

How many grams (g), liters (L), and meters (m) are in Megagrams (Mg), Megaliters (ML), and Megameters (Mm)?

1Mg = 1,000,000g 1ML = 1,000,000L 1Mm = 1,000,000m

What is the symbol and meaning for the prefix Mega?

Symbol: M Meaning: Milllion

How many centimeters are in an inch?

2.45cm

The Empire State Building is approximately 381 meters high. How many miles high is the Empire State Building?

0.237 miles

Change 0.00765 into mL

765 mL

What are the base units?

mass: in grams (g) volume: in liters (L) length: in meters (m)

how many sig. figs. are in the number 0.055870?

How many grams (g), liters (L), and meters (m) are in Kilograms (kg), Kiloliters (kL), and Kilometers (km)?

1kg = 1,000g 1kL = 1,000L 1km = 1,000m

A chemistry student’s height is measured at 68.5 inches. How tall is the student in cm?

17.4 cm

How many mm are equal to 4.75 x 10^-2 m?

47.5 mm

How many ML are equal to 4.567 x 10^4 mL?

4.567 x 10^-5 mL

How many seconds are there in 2.5 days?

21 seconds

How many Centigrams (cg), Centiliters (cL), and Centimeters (cm) are in grams (g), liters (L), and meters (m)?

100cg= 1g 100cL = 1L 100cm= 1m

How many centimeters are in a meter?

100 centimeters

How many inches are in a foot?

12 inches

(Vocab) Pure Substances + examples

Have uniform + definite composition Ex: Elements + Compounds

What is the difference between compounds and mixtures?

In compounds = elements are bonded to each other In Mixtures = the substances are blended (no definite composition - cannot assign a fixed ration)

Is breaking chalk a chemical or physical change?

Physical change

Is molding clay a chemical or physical change?

Physical Change

Is buring toast physical or chemical change?

Chemical change

Is rusting iron a physical or chemical change?

Chemical change

Give an example to show a measurement that is accurate and precise.

27.00 mL 27.00 mL 27.00 mL

What are the 2 major areas that matter is classified into?

1) Pure substances 2) Mixtures

Give an example to show a measurement that is neither accurate nor precise.

31.57 mL 25.06 mL 29.72 mL

Give an example to show a measurement that is precise but not accurate.

30.00 mL 29.97 mL 30.00 mL

What was the 1st idea of the atom?

The 1st idea of atom was from the Greek philosopher, Democritus. He believed that matter was composed of tiny indivisible particles called atoms. Since it was so long ago, and they had very little technology, he had no experimental evidence to support his thoughts.

State 4 major ideas of Dalton’s Atomic Theory:

1) All elements are composed of invisible particles called atoms 2) Atoms of the same element are identical. The atoms of any one element are diff. from those of another 3) Atoms of diff. elements mix or combine in whole number ratios 4) Chemical reactions occur when atoms separate, join, or rearrange. In a chemical reaction, atoms of another element NEVER change into another.

What is the experiment that led to the discovery of the electron?

The Cathode Ray Tube Experiment led to the discovery of an atom. There was a tube with insert gas and 2 plates, a positive and a negative one. The particles in the gas were attracted to the positive plate, and therefore we conclude that the particles must have a negative charge (opposites attract)

Explain Rutherford’s gold foil experiment.

Rutherford shot a high beam of positive alpha particles into a sheet of gold foil. Some of the particles were scattered/deflected which led to the conclusion that the atom has a tiny, hard, and dense crystal at the center of the atom, called the nucleus.

What are the 3 subatomic particles, what are their charges and where are they located?

Protons: positive charge, nucleus Neutrons: neutral, nucleus Electrons: negative charge, in the electron cloud outside the nucleus in energy levels.

What does the atomic number represent?

The number of protons in the element

What does the mass number represent and what is the formula to find it?

The number of protons and neutrons combined (protons + neutrons = rounded atomic mass/mass #)

What are isotopes? How are they the same? How are they different?

Isotopes are atoms with the same number of protons, but different number of neutrons. They are the same because they are all chemically alike, but the are different because they have different mass numbers.

What does the atomic mass represent?

The average (weighted) of all the element’s isotopes

What is an ion?

Atom or group that has a positive + negative charge.

What are the 2 ways in which you can form an ion?

1) When an atom gain electrons 2) When an atom loses electrons

What is density? What is the formula?

Density is the amount of mass per unit volume. Formula: D= m/v

Calculate the atomic mass of Carbon if the two common isotopes of Carbon have masses of 12 amu (98% abundance) and 13.003 amu (1.11% abundance)

12.011 = atomic mass of Carbon

Who discovered the proton?

Eugene Goldstein

Calculate the atomic mass of sulfur if the four common isotopes of sulfur have masses of 31.972 amu (95.00 % abundance), 32.971 amu (0.76%), 33.967 amu (4.22 %), and 35.967 amu (0.014 %).

32.05 = atomic mass of sulfur

Who discovered the neutron?

James Chadwick

Which scientist said that the atom was mostly empty space?

Ernest Rutherford

What is the formula for finding the number of neutrons?

Neutrons = mass # - atomic #

How are isotopes written?

Element - mass #