Chemisty | Chapter 2

Electric current (measurement)

ampere

How to interpret a graph

1) identify independent and dependent variables 2) look at the ranges of the data and consider what measurements were taken 3) decide if the relationship between the variables is linear or nonlinear 4) if the relationship is linear, is the slope positive or negative?

Which type of graph would you choose to depict changes in gasoline consumption over a period of ten years?

A bar graph because it shows how quantity varies with factors such as time, location or temperature.

What is the difference between a base unit and a derived unit?

A base unit is a defined unit in a system of measurement that's based on an object or event in the physical world. A derived unit is a unit that's defined by a combination of base units.

Luminous intensity (measurement)

Candela

Formulas of Denisty

Density= mass/volume Mass= density x volume Volume= density/mass

Explain why graphing can be an important tool for analyzing data.

Graphing can help you show data in an easier and more efficient way. With the help of circle graphs, bar graphs and line graphs, you can know the percentage or variation of your data.

Temperature (measurement)

Kelvin

Mass (measurement)

Kilogram

Describe the relationship between the mass, volume and density of a material

Mass is a measure of the amount of matter. Volume is the space occupied by an object. Density is the ratio that compares the mass of an object to its volume.

Amount of a substance (measurement)

Mole

What type of data can be displayed in a circle graph? Bar graph?

On a circle graph, you show parts of a fixed whole, percentages. With that, you can display data such as the amount of certain substances in a liquid. A bar graph shows how quantity varies, using heights of the bars. With this graph, you can display data such as the amount of rainfall in each month of a certain year.

Percent Error Formula

Percent error - accepted value answer/accepted value answer x 100

Accuracy

Refers to how close a measured value is to an accepted value.

Precision

Refers to how close a series of measurements are to one another; precise measurements show little variation over a series of trials but may not be accurate.

Explain why scientists, in particular, need standard units of measurements.

Scientists need to report data that can be reproduced by other scientists. The standard units of measurements allow their results to be accurate.

Bar graphs

Shows how a quantity varies with factors such as time, location, or temperature. The quantity being measured appears on the Y-axis and the independent variable appears on the X-axis. The heights of the bars show how the quantity varies.

Circle graphs

Shows parts of a fixed whole. The parts are labeled as percents, with the circle representing 100%.

Line graphs

The points on a line graph represent the intersection of data for two variables. The independent variable is on the X-axis and the dependent variable is on the Y-axis.

Length (measurement)

meters

Time (measurement)

seconds