Online Assessment
Instructions
1) Type in your first and last name in the
“Name” box in the top-left corner.
2) Next type in your teacher’s name in
the “ID” box.
3) Then type in your school’s full name in the
“Email” box.
4) Select the best answer for each question.
5) When you
are finished click the “Grade and Submit” button.
6) The grade will be emailed
to your teacher.
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1.
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NOTE: This assessment is only for Mr.
Elliott’s students.
---If you are not one of Mr. Elliott’s students then please go
back to the website and click on the link for other teachers. Thanks!
Three of the equations listed above are
unbalanced equations that DO NOT demonstrate the law of conservation of mass. One of these
equations, however, is a balanced equation.
Identify the
equation that correctly displays the law of conservation of mass.
a. | 2H2 + O  H2O | c. | H2 + O  2H2O | b. | 2H2 +
O2 
2H2O | d. | 2H2 + O  2H2O |
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2.
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A copper bar with a mass of 80 grams was left
outside under a tree. Oxygen in the air reacted with the bar forming rust called copper oxide. As the
bar rusted, its mass increased.
Choose the answer below that best explains how the mass
increased.
a. | The copper oxide released heat which caused the bar to
expand. | b. | Oxygen atoms combined with the copper atoms as the rust
was forming. | c. | Rust grew as it
absorbed energy from the copper bar | d. | Water was absorbed
as the rust formed on the copper bar. |
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3.
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In the equation below,
46 grams of sodium (Na) reacted with 36 grams of water (H2O).
If 2 grams of hydrogen gas (H2) is produced by this reaction, what is the mass of sodium hydroxide
(NaOH) produced?
a. | 80
grams | b. | 44
grams | c. | 82
grams | d. | 10
grams |
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4.
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| A student observed a chemical
reaction.
Sodium (Na) + Chlorine (Cl) yields Sodium Chloride
(NaCl) | | | | |
She wrote an equation about this that correctly displayed the law of
conservation of mass.
Select the balanced equation below that she wrote about this chemical
reaction.a. | 2Na + Cl2  3NaCl | c. | 2Na + 2Cl2  2NaCl | b. | Na +
Cl2  2NaCl | d. | 2Na +
Cl2  2NaCl |
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5.
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No mass is created or destroyed in chemical
reactions according to the law of conservation of mass.
Which procedure best represents
the law of conservation of mass?
a. | exploding a 30g stick of dynamite leaving behind only a
5g piece of the stick | b. | using a magnet to
separate 5 grams of metal flakes from 10 grams of sand | c. | combining 6g of hydrogen & 3g of oxygen to produce 9g of dihydrogen
monoxide | d. | boiling 10 grams of salt water
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6.
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Students have two
identical beakers with a mass of 20 grams each. The students pour a different liquid reactant into
each beaker. The total mass of the two beakers with the reactants is 50 grams. Next, the students
combine Reactant 1 and Reactant 2 into one of the beakers. A chemical reaction produces a
product.
If all of the reactants are consumed and no gases are produced, what is the
total mass of the product and one beaker?
a. | 30
grams | b. | 40
grams | c. | 70
grams | d. | 20
grams |
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7.
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A
student observes a chemical reaction. | Aluminum (Al) + Oxygen (O)
yields Aluminum Oxide (Al2O3) | |
She writes an equation that correctly displays the law of conservation of
mass.
Select the balanced equation below that she wrote about this chemical
reaction.a. | 2Al + 3O3  2Al2O3 | c. | 4Al + 3O2  2Al2O3 | b. | Al +
O2  Al2O3 | d. | 4Al +
2O2  3Al2O3 |
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8.
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A student asks why the ashes from a fire have a
much lower mass than the wood that was burned.
Which is the correct answer to the
students question?
a. | Heat causes molecules to lose
density. | b. | Atoms in the wood are
destroyed. | c. | Gases are released
into the air. | d. | Water inside the
wood solidifies. |
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9.
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A chemical reaction occurs when you cook outside
using a propane grill.
The reactants are propane (C3H8) and oxygen
(O2).
The products are water (H2O) and carbon dioxide
(CO2)
Which equation correctly represents
this reaction?
a. | CH8 + 5O2
 4H2O +
3CO2 | b. | C3H8 + O2  4H2O + 3CO2 | c. | C3H8 + 5O2  4H2O + CO | d. | C3H8 + 5O2  4H2O + 3CO2 |
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10.
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No matter is created or destroyed in any chemical
reaction according to the law of conservation of mass.
Which sample equation
best illustrates the law of conservation of mass?
a. | 4 grams reactant U + 3 grams reactant V à 7 grams product W | b. | 12 grams reactant
X + 10 grams reactant Y à 2 grams product
Z | c. | 5 grams reactant E + 5 grams reactant F à 20 grams product G | d. | 10 grams reactant
Q + 9 grams reactant R à 90 grams product S
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