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WorksheetsElements, Compounds, Physical, and Chemical Changes
Total questions: 16
Worksheet time: 33mins
Ryan is using the chemical formulas for various substances to classify them as either a compound or an element. Which of the following should he identify as a compound?
Fe
CO
C
Co
Rebecca is using the chemical formulas for various substances to classify them as either a compound or an element. How should Rebecca classify Gold (Au)?
Gold is a compound composed of a blend of substances.
Gold is an element composed of a blend of substances.
Gold is a compound composed of a pure substance.
Gold is an element composed of a pure substance.
Which of the following lists contains only elements and a reason why they are elements?
H2O, NaCl, N2, CO2 – Substances are elements because they contain more than one chemical symbol.
Kr, Ne, Ar, He – Substances are elements because they are all noble gases.
Cl2, H2, Na, He - Substances are elements because they are pure.
F2, O3, Li, H – Substances are elements because they all have chemical symbols.
The instructions for a lab warned students to avoid putting Na in the liquid used during the experiment. What element should not be placed in the liquid?
Nitrogen
Phosphorus
Sodium
Silicon
Which of the following students best describes an element?
Student 1- Elements are chemicals that are pure substances held together by chemical bonds.
Student 2- Elements are mixtures of protons, neutrons, and electrons in different combinations.
Student 3- Elements are chemicals that are pure substances represented by symbols that have at least 1 capital letter.
Student 4- Elements are chemicals that are formed when a temperature change happens or a precipitate forms.
Student 1
Student 2
Student 3
Student 4
The two products to the right of the arrow in the chemical equation above are best classified as —
MCO3 → MO + CO2
one compound and one element
two elements
one element and two compounds
two compounds
Which of the following substances is a compound?
C
NH3
Co
K
Flour, sugar, cocoa, oil, and eggs are mixed together and placed in the oven to make brownies. When the brownies are removed from the oven, they no longer look like the original ingredients.
Which of the following describes why the ingredients changed?
A biological change occurred.
No change occurred.
A physical change occurred.
A chemical change occurred.
Students performed an investigation to see what would happen when sugar is exposed to heat. The students' observations are listed below.
Student Observations
A * The sugar melted.
B * The sugar began to bubble and turned a brown color. It smelled like caramel.
C * The sugar turned black and began to give off smoke.
D * The sugar began to bubble as it melted.
Which students’ observations indicate that a new substance formed as a chemical change occurred?
Student A and Student C
Student B and Student C
Student A and Student D
Student B and Student D
After an investigation, students were disposing of left over substances. One student poured all of the liquids down the sink drain. A few seconds later, a white cloud formed above the sink and the student’s eyes began to burn.
Which statement accurately describes what caused this occurrence?
The student did not wait two minutes in between pouring each liquid down the drain.
The student did not allow water to run in the sink after pouring each liquid down the drain.
A physical change occurred resulting in the formation of a new substance.
A chemical change occurred resulting in the formation of a new substance.
Two liquids are mixed together. Which of the following does NOT identify the formation of a new substance?
A gas is produced.
One liquid dissolves into the other.
The temperature changes.
A solid is formed.
A student had a beaker with a small amount of baking soda. The student added a few drops of pickle juice to the baking soda and observed fizzing and bubbling.
Based on observation, which of these can the student conclude?
A chemical reaction produced a solid.
No chemical reaction took place.
Only a physical change happened.
A chemical reaction produced a gas.
A substance that is solid, has a shiny orange color, conducts electricity well, and melts when heated could MOST likely be classified as a —
Non-metal
semi-conductor
metalloid
metal
Students were given four unknown substances and asked to observe their characteristics. Their observations are shown in the table below:
Which of the unknown substances is MOST likely a metal?
1
2
3
4
A student finds that the mass of 25mL of an unknown liquid is 20.5g. What is the density of this substance?
D= M/V or M=DxV or V=M/D
0.82
51.25
1.22
The density of pine is less than the density of oak. Density determines whether an object will float.
This means that —
The oak boat will sit higher in the bucket of water because it is less dense.
The oak boat will sit lower in the bucket of water because it is less dense.
The pine boat will sit higher in the bucket because it is less dense.
The pine boat will sit lower in the bucket of water because it is less dense.
