Chapter 3 Key Concepts Flashcards
How are accuracy and precision evaluated?
The measured value must be compared to the correct value to evaluate the accuracy. To evaluate the precision, you must compare the values of two or more repeated measurements
How do measurements relate to experimental science?
Measurements are fundamental to experimental sciences. For that reason, it is important to be able to make measurements and to decide whether a measurement is correct
Why must a given measurement always be reported to the correct number of significant figures?
Calculated answers often depend on the number of significant figures in the values used in the calculation
How does precision of a calculated answer compare to the precision of the measurements used to obtain it?
In general, a calculated answer cannot be more precise than the least precise measurement from which it was calculated
Which 5 SI base units are commonly used in chemistry?
Meter, kilogram, kelvin, second, mole
Which metric units are commonly used to measure length, volume, mass, temperature, and energy?
Common metric units of length include the cm, m, and km. common metric units of volume include L, mL, cubic cm, and microL. Common metric units of mass include the kg, g, mg, and microg. Scientists commonly use two equivalent units of temperature, the degree C and the K. Common units of energy are the joule and the calorie
What happens to the numerical value of a measurement that is multiplied by a conversion factor? What happens to the actual size of the quantity?
The numerical value is generally changed but the actual size of it remains the same.
Why is dimensional analysis useful?
It provides you with an alternative approach to problem solving
What types of problems can be solved using dimensional analysis?
Problems in which a measurement with 1 unit is converted to an equivalent measurement with another unit
What determines the density of an object?
Density is an intensive property that depends only on the composition of a substance , not on the size of the sample
How does density vary with temperature?
It generally decreases as its temperature increases
