Accuracy vs. Precision
A measure of reproducibility of a measurement
What is precision?
The number of significant figures in the 2,589,500
What is 5?
Which of these represents the largest amount of time?
1 second
1 picosecond
1 nanosecond
1 second
Carbon, nitrogen, and oxygen are examples of this.
What are elements?
These are variants of an element that have the same number of protons, but a different number of neutrons.
What are isotopes?
A measure of how close the measurement is to the true value
What is accuracy?
When multiplying or dividing, how do you know how many sig figs should be in the answer?
The number of sig figs in the answer should be equal to the lowest number of sig figs in the question.
Would converting 4.59 cm to nanometers yield a number that is bigger or smaller than 4.59?
Milk, salad dressing, and lemonade are examples of this.
What is a mixture?
True or false: the atomic mass, which is on the bottom part of each element's block on the periodic table, tells you the atomic mass of the most abundant isotope of the element.
FALSE! This is an average based on all of the isotopes & their abundances.
**Dr. Wren said he will put this on a test :)
These are used to communicate the accuracy of a measurement.
What are significant figures?
2.356/4.19 =
The number of significant figures in the quotient should be...
What is 3 sig figs?
Which represents more fluid? 5000 milliliters (mL) of water or 7,000,000 microliters (uL) of water
What is 7,000,000 microliters?
A non-uniform mixture.
What is a heterogeneous mixture?
Elements in the periodic table are organized left to right in order of increasing ________, which signifies the number of ________ in an element.
Atomic number, protons
I measure a piece of metal 3 times, getting masses 2.2555 g, 2.2552 g, and 2.2554 g. As it turns out, the true mass of the metal is 2.2552 g! How would you describe my measurements?
Both accurate AND precise
This is an important rule when adding or subtracting numbers in order to determine the number of sig figs in the sum or difference.
What is lining up the decimal points?
The number of significant figures in the answer is determined by whichever number has the least decimal places.
Which of the following relationships is incorrect?
1 microliter = 10-6 liters
1 megagram = 106 grams
1 milliliter = 103 liters
100 centimeters = 1 meter
1 milliliter does NOT equal 103 liters, it equals 10-3 liters.
A substance formed when two or more different elements are bonded together.
What is a compound?
Which element has the chemical symbol Fe? How many protons does it have?
Iron, 26 protons
What is accuracy?
(53.62 g - 52.7 g)/8.67 mL
What is 0.1 g/mL?
Knowing that 1 L =1.06 quarts, what is 4301 mL in quarts (qt)?
A group of 2 or more atoms bonded together, the smallest unit that can participate in a chemical reaction
What is a molecule?
How many protons, neutrons, and electrons are in oxygen?
p - 8
n - 8
e- - 8