Nature of Science
What should a scientist do if his experiment does not support his hypothesis?
Revise the hypothesis and repeat the experiment.
What is the smallest unit of an element?
atom
A student has a container of sand and sugar. What could be used to separate the mixture?
solubility or water and a filter
What happens to the motion of the particles when energy is removed?
The motion of the particles slow down.
Is ice melting a physical change or a chemical change?
physical
What is the difference between science and pseudoscience?
Science is testable, pseudoscience is not.
What part of the atom contains almost all the mass?
the nucleus
Sugar is added to water, tea and ice, then stirred until the sugar dissolves. How is this tea classified?
Element, Compound, Solution or Pure Substance
Solution
Which state of matter are the particles the most attracted to each other and only vibrate in place?
solids
What is true about ALL chemical reactions?
a new substance is formed
What causes a scientific theory to change?
Theories can change over time with new evidence.
Elements on the periodic table that are in the same group or column have
similar properties
What pH numbers would be considered a strong acid?
0, 1, 2, or 3
What is the mass of an object that has a volume of 45 cm3 and a density of 2.336 g/cm3?
.0519
If a piece of paper is burned and the ashes weigh less than the original paper, where is the remaining mass?
smoke and gases
How can you support a scientific claim or results of a scientific experiment?
evidence
Atoms contain electrons which orbit around the nucleus which is made of what?
Are dried pineapple, raisins, seeds, and nuts a homogeneous or heterogeneous mixture?
heterogeneous mixture
What is the density of an object with a mass of 67.55 g and a volume of 3.5 cm3?
19.3 g/cm3
How can you increase the rate of a chemical reaction?
raise the temperature
Does the shape of a car affect wind resistance? What is the independent variable?
shape of the car
Why did the model of the atom change so much over time?
new technology and new evidence
Litmus paper turns red in acids and blue in bases. What color would the paper turn if the solution tested was considered basic?
blue
If the density of water is 1 g/mL, would an object with a density less than 1 g/mL sink or float?
float
A bottle of milk in the refrigerator stays fresher longer than leaving it out at room temperature. If the freshness is related to a chemical reaction, explain why milk stays fresher in the refrigerator.
The lower temperature of the refrigerator reduces the rate or slows down the chemical reaction.