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Semester 2 Final
BJHS semester 2 final exam
Question | Answer |
---|---|
A liquid mixture in which particles can be seen and easily separated by settling or filtration is a? | suspension. |
When you add so much solute that no more dissolves, you have a? | saturated solution |
What is one way to increase the solubility of sugar in water? | Heat the water |
Acids are described as corrosive because they? | “eat away” at other materials |
The pH scale measures? | the concentration of hydrogen ions |
One example of a physical change is? | dissolving salt in water |
One example of a chemical change is? | burning wood. |
The energy of matter in motion is called? | kinetic energy |
Radio waves, visible light from the sun, infrared “rays” from heat lamps, the waves that heat food in a microwave oven, ultraviolet rays, and X-rays are all considered types of? | electromagnetic energy |
Table sugar and table salt are examples of? | pure substances |
Substances that CANNOT be broken down chemically into other substances are? | elements |
The measurement of the force of gravity on an object is the object’s? | weight |
All elements are composed of extremely small particles called? | atoms |
The ability to do work or cause change describes? | energy |
The change in which ice absorbs energy and melts is a(n)? | endothermic change |
Each family in the periodic table has its own characteristic properties based on the number of? | valence electrons |
When an atom loses an electron, it becomes a? | positive ion. |
What is the chemical name for the compound with the formula Na2S? | sodium sulfide |
What is the greatest number of valence electrons an atom can have? | 8 |
If atoms of a halogen nonmetal (Group 17) gain one electron, the atoms then have? | 8 valence electrons. |
Which of the following is NOT a correct inference that you can make about the burning of gasoline? | The reaction is a physical change. |
Anything that has mass and takes up space is considered? | matter. |
The only sure evidence for a chemical reaction is? | the production of one or more new substances. |
As in the case of unlike magnetic poles, unlike electric charges? | attract each other. |
The loss of static electricity as electric charges move off an object is called? | static discharge. |
What causes charges to move in a circuit? | voltage |
An electric current will always follow? | the path of least resistance. |
In a series circuit with three bulbs what will happen to the light bulbs when energy is applied? | all of the bulbs become dimmer as more bulbs are added. |
In a parallel circuit with three bulbs what will happen to the light bulbs when energy is applied? | current from each bulb has its own path. |
What is a disadvantage of using fuses? | When a fuse burns out, it cannot be used again. |
What effect would a current of greater than 0.2 amp have on your body? | It could cause burns and stop your heart. |
Mendeleev created the first periodic table by arranging elements in order of? | increasing atomic mass. |
How did chemists change Mendeleev’s periodic table in the early 1900s? | They used atomic number instead of atomic mass to organize the elements. |
Which of the following scientists inferred that an atom’s positive charge must be clustered in the nucleus? | Ernest Rutherford |
Most metals are NOT what state of matter at room temperature? | liquid |
In the periodic table, the most reactive metals are found where? | in Group 1, the first column on the left. |
Which group contains the most elements? | metals |
A material is said to be ductile if it? | can be pulled out, or drawn, into a long wire. |
In an atom, the number of protons equals the number of? | electrons. |
The elements in a column of the periodic table have what in common? | have similar properties. |
Energy is measured in units called? | joules. |
An example of something that stores chemical energy is? | a match. |
Moving water can be used to produce electricity because? | most forms of energy can be converted into other forms. |
What type of conversion is taking place when natural gas is used to heat water? | chemical energy into thermal energy |
An example of a fossil fuel is? | petroleum. |
Fossil fuels contain energy that originally came from? | the sun. |
The type of energy stored by fossil fuels such as coal is? | chemical potential energy. |
Potential energy that depends on height is called? | gravitational potential energy. |
When generators are spun by turbines, they produce what? | electricity. |
What type of energy does a spinning turbine have? | mechanical energy |
Energy stored in the nucleus of an atom is called? | nuclear energy. |
Visible light is an example of what kind of energy? | electromagnetic energy. |
Niagara Falls is a good example of what kind of energy? | potential energy being converted into kinetic energy. |
The law of conservation of energy states that when one form of energy is converted into another what happens to the total amount of energy? | no energy is destroyed in the process. |