Chemistry- chapter 3 test

Significant digits only apply to....

Measured data

Nano

billionth (10^-9)

Centi

hundredth 10^-2

Which of these has the greatest number of significant digits: 45620 cars, 3.35 m, or 35000 mL

45620 cars (4 significant digits)

What is the difference between accuracy and precision

Accuracy refers to the closeness of a measured value to a standard or known value. Precision refers to the closeness of two or more measurements to each other. Ex. Right on the bullseye- accuracy All darts are on/around the same spot

What is a significant digit? Why is it used?

All the certain digits plus one estimated digit They determine all the important digits you need to record in the measurement and they indicate precision of the measurement

Units of measurement that come from basic SI units units are called...

Base units

Be able to find volume, density and mass

D= M/V

A perfect measurement can be obtained

False

The unit of volume is derived from the SI unit for length (the meter)

False

When solving problems that involve compound calculations, it is best to round off at each of the intermediate steps

False

Any artificial device made for the purpose of refining, extending, or substituting for the human senses when measuring is called a(n)

Instrument

Describe what is meant by "bridge notation" and explain its value

It is used to multiple and divide several measurements at the same time and is primarily used for converting units.

Be able to convert between the metric systems

KHDUDCM (king, henry, died, unexpectedly, drinking, chocolate, milk

Be able to figure out significant digits, know the rules?

Knowing how to round up an answer 4203.00_ how many significant digits are there? There are 4 significant digits 300.02_ how many significant digits are there? There are 5 significant digits 300_ how many significant digits are there? There is one significant digit 300.0_ how many significant digits are there? There are 3 significant digits

Give four of the seven base units of the SI and the basic dimension that each represents.

Length- meter, time-seconds, mass- kilogram, temperature- kelvin

Be able to calculate density, mass, and volume

Mass/ Density * volume Mass= grams (g) , density= grams/milliliter (g/ml), volume=milliliter (ml) Ex. A block of aluminum occupies a volume of a 15.0 mL and a mass of 40.5 g. What is density? 40.5/15.0= 2.7/ml

the result of comparing an unknown quantity to a standard unit is called a/an

Measurement

What is a mole in chemistry

Number of particles in a substance

Which of these would yield a measurement with the greatest precision? (Oven thermometer, oral medical thermometer, pool thermometer, or outdoor Esther thermometer) why?

Oral medical thermometer, because it's made to be more precise

Be able to calculate percent error

Percentage error = measured value - true value/ True value

When is it important to express numbers with the proper number of significant digits?

So we can be precise and accurate

What are the common steps in problem solving? What is the first step in problem solving?

Step 1- read the statement of the problem Step 2- determine the method of solution Step 3-choose the specific tool to use Step 4- set up the problem, estimate, and calculate Step 5- check and format The first step is read the statement of the problem

You measure products of a chemical reaction to be 4.15g, 4.16g, and 4.13g. The actual mass is 4.14. How would you describe the accuracy and precision of these measurements?

The products are accurate because they are close to the actual mass but they aren't precise because they are all really close to eachother

You measure the products of a chemical reaction to be 4.52g, 3.29g, and 2.29g. The actual mass is 3.65g, how would you describe the accuracy and precision of these measurements?

They aren't accurate or precise because all the measurements are far off from the actual mass.

Measurements can be used to fulfill God's commands

True

The number 0.000640 mL should be expressed as 6.4*10-4 ml in scientific notation to eliminate ambiguity in its precision

True

A measurement is made of two essential parts. What are the two parts?

a number and a unit of measure

What is conversion factor?

a ratio of equivalent values having different units

What is the metric system?

a system of measurement based on the number 10

What does graduated mean in measurement

accurately subdivided into measurement units

What's the difference between analog and digital?

analog signals have continuous electrical signals, while digital signals have non-continuous electrical signals.

Mega

million (10^6)

Micro

millionth (10^-6)

Deci

tenth 10^-1

Kilo

thousand (10^3)

Milli

thousandth (10^-3)