Elements/Periodic Table
Which of the following is the symbol for chlorine?
Cl
Which of the following statements are characteristics of a compound?
I. Compounds are made from two or more elements.
II. A compound is a pure substance.
III. Compounds are represented by a chemical symbol.
IV. Compounds are represented by a chemical formula.
I,II, IV
MCO3 → MO + CO2
The two products to the right of the arrow in the chemical equation above are best classified as:
A. One compound and one element.
B. Two elements.
C. One element and two compounds.
D. Two compounds.
D. Two compounds.
When vinegar and baking soda are combined, bubbles and foam are produced. What evidence demonstrates that a chemical change has occurred?
A. A color change occurs.
B. A gas is formed.
C. A solid has dissolved.
D. A precipitate is formed.
B. A gas is formed.
Process: Characteristics
A: Salt or sugar dissolves in hot water.
B: The formation of a precipitate.
C: Temperature change.
D: Adding food coloring to cake icing to change the color.
E: Gas is released as vapor or bubbles.
F: Chemicals in fireworks explode into brilliant colors and give off smoke when exposed to a flame.
Which processes above can be used as evidence to identify the formation of a new substance?
Processes B, C, E, and F
Which of the following statements are characteristics of an element?
I. Elements are made from a mixture.
II. An element is a pure substance.
III. Elements are represented by a symbol.
IV. Elements make up matter.
II, III, IV
Which of the following substances represents a compound?
1. Cr
2. KF
3. H2SO4
4. Cs
5. Al2O3
6. CaO
2, 3, 5, and 6
The following is a chemical equation that represents the law of conservation of mass.
8 CO + 17 H2 → C8H18 + 8 H2O
Which substance in the above equation is represented by an element?
H2
Which example provides evidence of a chemical change?
A. Wood releases ash and smoke when burned.
B. Rock particles separate when soil is being sifted.
C. Boiling water bubbles when being heated.
D. Sugar is not visible when dissolved in water.
A. Wood releases ash and smoke when burned.
Students performed multiple investigations at different stations in the classroom. The date collected is listed below.
Station 1: When vinegar was mixed with milk, white chunks formed and fell to the bottom of the beaker.
Station 2: When blue food coloring was added to cold water, the water slowly changed colors. When red food coloring was added to hot water, the water rapidly changed colors.
Station 3: A balloon filled with a white powder was sealed around the mouth of a bottle containing a liquid. When the balloon was lifted to dump the power into the liquid, bubbles and foam formed and the balloon inflated with air.
Station 4: When a marshmallow was extended over a flame, it first turned brown, and then it turned black and became hardened.
Station 5: Sugar was added to ice water and stirred for one minute. After two minutes passed the sugar was visible in the bottom of the beaker.
Station 6: 200 mL of water was added to a beaker and placed on hot plate. Five minutes after the water began to boil, there was less than 200 mL of water remaining in the beaker.
The observations from which investigations provide evidence that a new substance was formed?
Stations 1, 3, and 4
Which of the following substances represents an element?
1. CO
2. Ag
3. HI
4. CN-
5. Db
6. Xe
2,5, and 6
A new compound has just been developed. Its formula is C17H2ON4NaO9P. How many different elements make up this compound?
7
A. Water is not a pure substance, but is an element.
B. Water is a pure substance and an element.
C. Water is a pure substance and a compound.
D. Water is not a pure substance, but is a compound.
C. Water is a pure substance and a compound.
Two liquids are mixed together. Which of the following does NOT identify the formation of a new substance?
A. A gas is produced.
B. One liquid dissolves into the other.
C. The temperature changes.
D. A solid is formed.
B. One liquid dissolves into the other.
A student had a beaker with a small amount of baking. The student added a few drops of pickle juice to the baking soda and observed fizzing and bubbling. Based on observation, what can the student conclude?
A chemical reaction produced gas.
Which of the following do NOT describe an element?
1. A mixture of different chemicals.
2. Represented by a symbol that contains one uppercase letter.
3. Represented by a symbol that can contain a second uppercase letter.
4. Represented by a symbol that can contain a lower case letter.
5. A pure substance.
6. Can be identified using the periodic table.
1 and 3
During a science class investigation, a teacher places a small amount of sugar in a beaker and heats it over a candle. Which of the following would be the best evidence that a change in the chemical properties of the sugar has taken place?
A. The sugar gets hotter.
B. The sugar gets larger.
C. The sugar turns into a liquid.
D. The sugar turns black.
D. The sugar turns black.
Sodium is a highly reactive, soft metal. Chlorine is a poisonous, green gas. These elements combine to form sodium chloride (table salt), which is a white solid that can be safely eaten.
Which claim is supported by the information?
A. Table salt is an element.
B. Table salt is a mixture of elements.
C. Table salt is a compound.
D. Table salt has similar properties to sodium.
C. Table salt is a compound.
What causes a bicycle to rust when it is left outside in the weather? Why is rust evidence of a chemical change?
The oxygen reacts with the metal causing rust to form. Rust is a chemical change because it is a new substance.