Test 1- Measurements and Metric Flashcards
Lab Safety
- If you or your partner is hurt, immediately yell out “Code one. Code one” to get the instructor’s attention
- Common sense. Don’t be stupid
PH scale
- PH=Power H+
- Acids- less than 7
- Bases- greater than 7
Caustic & Volatile
- Caustic- acid- burns flesh
- Volatile- harmful/dangerous
Observation vs. Inferences
- Observation- uses your senses
- Inference- Based upon previous knowledge
7 dynamic elements
Br, I, N, CI, H, O, F
- Really reactive
- Hook up with each other or other other atoms
Density formula
Density= Mass/Volume
Use of measuring instruments
- Set balance to zero
- Always guess one more digit than the device goes
Fundamental quantity
unchanging in nature
7 fundamental quantities
- Luminous intensity, Temperatire, Mass, Amount of substance, Electric current, Time, Distance/Length
- Little Timmy May Always Eat Ten Doughnuts
Luminous intensity is measured in
Candelas
Temperature is measured in
Kelvin
Mass is measured in
Kilograms
Amount of substance is measured in
Moles
Electric current is measured in
Ampere
Time is measured in
Seconds
Distance/Length is measured in
Meters
Derived quantities
Based on fundamental ones and have formulas
Water freezes/boils
- Celsius- 0/100
- Fahrenheit- 32/212
- Kelvin- 273/373
Absolute zero
-273c
Formula for Kelvin
273+C=K
Extrapolated
Extended trend beyond data
Catalyst
Speeds up chemical reaction without being changed
Staircase
Kilo (k) Hecto (h) Deka (da) BASE (m,l,g) Deci (d) Centi (c) Mili (m) SKIP SKIP Micro (u w/ tail) SKIP SKIP Nano (n) SKIP SKIP Pico (p)
Staircase down
Multiply by 10; move decimal to the right
Staircase up
Divide by 10; move decimal to the left
Staircase acronym
King Henry Died By Drinking Chocolate Milk SKIP SKIP Micro SKIP SKIP Nano SKIP SKIP Pico
Scientific Notation
- Used to write really big/small numbers in a simple way
- Move the decimal over until the number is greater than or equal to 1, but less than 10
- Count how many places you moved the decimal. However many it is, is the number you put as the exponent
- If you moved the decimal to the right, the exponent is negative because the original number is smaller than the number now in scientific notation
- If you moved the decimal to the left, the exponent is positive because the original number is bigger than the number now in scientific notation
Significant digits- Atlantic/Pacific rule
- If there is a decimal present, start counting from the left starting with the first non zero digit
- If there is not a decimal present, start counting from the right, starting with the first non zero digit.
Significant digits- adding/subtracting
- First identify the guessed digit in each number (the last digit of the last number of each number in the problem)
- After adding/subtracting, the guessed digit with the highest place value will be used in the answer
Significant digits- Multiplying/dividing
- Count the number of digits in each number and the lowest number is the number you will round your final answer to
- Your answer needs to have that many significant digits
Accuracy vs. Precision
- Accuracy- The closeness of measurements to the correct or acceptable value of the quantity measured
- Precision- The closeness of a set of measurements of the same quantity made in the same way
Percent error
- Used to calculate how close the the correct answer you were
- Equation- Experimental value (what you got) - accepted value (correct answer) divided by accepted value (correct answer), times 100
Dimensional analysis
- aka factor label
- Use staircase method to figure out base-prefix ratio
- Start with given value on top and multiply until you end with the desired value on top, making sure units cancel as you go
Conversion factors
1m/100cm & 100cm/1m
quarts to gallons
4 quarts=1 gallon
Pints to quarts
2 pints=1 quart
cups to pints
2 cups= 1 pint
inches to feel
12 inches=1 foot
inches to yards
36 inches=1 yard
feet to yards
3 feet=1 yard
fl oz to cups
8 fl oz=1 cup
oz to pounds
16 oz=1 pound
Answer in dimensional analysis
- These unit equalities are infinitely significant
- The answer in dimensional analysis has the snake number of significant digits as the given value
Qualitative
Data based on information that’s not number but descriptive
Quantitative
Data based on numbers
Mole
the SI base unit used to measure the amount of a substance whose number of particles is the same as the number of atoms of carbon in exactly 12 g of carbon-12
Density
- the ratio of the mass of a substance to the volume of the substance; commonly expressed as grams per cubic centimeter for solids and liquids and as grams per liter for gases.
- D=m/v
Volume
- a measure of the size of a body or region in three-dimensional space.
- LxWxH
Area
L X W
Matter
anything that has mass and takes up space
Parts of a formal lab report-
- Title:
- Purpose: background info, why were doing it
- Materials: amounts, chemicals, glassware, equipment
- Procedure: step by step, detailed, include diagrams when needed
- Data: Only what you see, small, hear, etc. Qualitative and Quantitative (numbers and observations), no calculated values
- Data analysis: Answer post-lab questions, do all calculations, and include all labels, graphs, analysis of graphs
- Conclusion: Give examples from lab of how you addressed the purpose, discuss all sources or error in procedure, percent error
Lab safety
Lab safety ensures your safety while doing labs and makes sure you are doing them correctly both to get accurate data and be safe while doing it. No beverages/food, read directions and follow, keep isles clear, always stand, wear proper equipment, keep sharp tips away, no contact lenses, tie hair back, Use tongs and gloves with hot stuff, don’t leave burner unattended, point open end of burning tube away, study the handout
Balance
measures mass in grams
Thermometer
Measured temperature in celcius
Ruler
Measures length in centimeters and inches
Graduated cylinder
Measured volume in mL
