Experimental Design
What is the name of the variable that is being tested or changed in an experiment?
The Independent Variable
Bar, Line, Scatter Plot, Pie
Name a physical property
Color, Texture, Mass, Volume, Density, Odor, etc.
Name a chemical property
Flammability, Toxicity, Reaction with air, Reaction with water, Acidity, etc.
What is the formula for calculating Density?
D=M/V
Identify the dependent variable in this experiment: How does the amount of fertilizer affect plant height?
Plant Height
Dependent on the "Y" (DRY)
Independent on the "X" (MIX)
Define a physical property
Something you can measure or observe without changing the composition of the substance
Define a chemical property
Something you can only observe when changing the matter.
What is the unit for density?
g/cm3 or g/mL
What is a constant in an experiment?
The things you keep the same amongst all of the groups
What should be included in a graphs title?
Both variables (the label from the x & y OR the independent and dependent variable)
In which state of matter are particles spread the farthest and therefore have the highest energy?
Gas
Name some examples of elements (2) that are highly reactive with water
Alkali Metals (lithium,sodium, potassium, rubidium, caesium).
Displacement- measure water level before and after adding object. The difference is the objects volume (irregular shaped objects)
LxWxH for cubes or rectangular prisms
Create a full hypothesis for the following experiment:
A baker wanted to figure out which type of sugar made the softest chocolate chip cookies. They bought brown sugar, powdered sugar, and granulated sugar.
If a baker uses _______________ (brown, powdered, granulated), then the chocolate chip cookies will be the softest.
What is an interval/scale on a graph?
It is the amount each line is worth on a graph, or what you are "counting by". For example, each line up the Y axis might be two. Or every other line could be 10 making the interval 5.
Explain the reason why solubility is a considered physical property?
Solubility is a physical property because you are not creating something new, and you can get the same starting materials back. For example, when you add sugar to water and it dissolves, it is still simply sugar and water. You could evaporate the water and be left with plain sugar at the end.
Name 4/6 of the indicators that a chemical change has occured?
What is the difference between weight and mass?
Mass is how much matter is inside something and never changes. Weight is the force acting on an object due to the acceleration of gravity. Weight changes depending on gravity.
Identify all aspects of the following experiment;
A student is testing how different liquids impact the time it takes for an iron nail to rust.
Independent Variable:
Dependent Variable:
Constants (3)
Control Group:
Experimental Group:
Independent Variable: Type of liquid
Dependent Variable: Time to rust
Constants (3): same nail size, same amount of liquid, same room, etc
Control Group: nail in water
Experimental Group: nail in different liquids (oil, salt water, soda, milk, etc)
Name all of the aspects you need to include in a graph.
- Title
-Labels on X and Y axis
- Units
-Interval or Scale
- Data plotted correctly
-Key (if it applies)
What is the name of the phase change when a solid turns directly into a gas, skipping the liquid phase?
Sublimation
What is the scientific (chemical name) for rust?
Iron Oxide
Solve this problem from start to finish and show work (INCLUDE ALL UNITS AND FORMULAS OR NO POINTS!!!!!!)
A student is given a mystery sample with a length of 2.5 cm, width of 2.0 cm, and height of 2.0 cm. They put it on a scale and find that it's mass is 12.4 g. What is the Density of this sample?
Would this sample sink or float in water? Explain.
Volume = LxWxH
V= 2.5x2.0x2.0
V= 10 cm3
D=M/V = 12.4g/10cm3
D= 1.24 g/cm3
This would sink in water because it has a density greater than 1.0 which is water's density.