Matter Interactions Unit Test
1 of 131 of 13 Items
Question
Cobalt has a mass number of 59 and an atomic number of 27. A student wants to create a model of a cobalt atom. Which statement about the model is correct?(1 point)
Responses
The model should show 27 protons and 32 neutrons.
The model should show 27 protons and 32 neutrons.
The model should show 27 protons and 27 neutrons.
The model should show 27 protons and 27 neutrons.
The model should show 32 protons and 59 neutrons.
The model should show 32 protons and 59 neutrons.
The model should show 59 protons and 27 neutrons
The model should show 27 protons and 32 neutrons.
To determine the correct statement about the model of a cobalt atom, we need to understand the meaning of the mass number and atomic number. The atomic number represents the number of protons in an atom, while the mass number represents the total number of protons and neutrons.
In this case, the question states that cobalt has a mass number of 59 and an atomic number of 27.
Hence, the correct statement about the model of a cobalt atom is: "The model should show 27 protons and 32 neutrons."
The correct statement about the model is: The model should show 27 protons and 32 neutrons.
In a molecule of lithium sulfide, there are two atoms of lithium and one atom of sulfur. Which statement about lithium sulfide is correct?(1 point)
Responses
Both lithium and sulfur form positive ions.
Both lithium and sulfur form positive ions.
A molecular model of lithium sulfide would have two spheres.
A molecular model of lithium sulfide would have two spheres.
The atoms in lithium sulfide are held together by bonds.
The atoms in lithium sulfide are held together by bonds.
The chemical formula for lithium sulfide is LiS2.
The atoms in lithium sulfide are held together by bonds.
Which element has the same number of valence electrons as bromine (Br)?
(1 point)
Responses
chlorine (Cl)
chlorine (Cl)
potassium (K)
potassium (K)
krypton (Kr)
krypton (Kr)
selenium (Se)
chlorine (Cl)
Why are sodium (Na) and potassium (K) in the same group on the periodic table?(1 point)
Responses
They are both hard and brittle.
They are both hard and brittle.
They have similar atomic weights.
They have similar atomic weights.
They are both colorless.
They are both colorless.
They have similar reactivity.
They have similar reactivity.
A student cuts some fabric into two pieces. Is this change physical or chemical?(1 point)
Responses
It is a physical change because there is no reaction.
It is a physical change because there is no reaction.
It is a chemical change because there is no phase change.
It is a chemical change because there is no phase change.
It is a chemical change because the size changes.
It is a chemical change because the size changes.
It is a physical change because the process is reversible.
It is a physical change because there is no reaction.
How are chemical changes different from physical changes?(1 point)
Responses
They form new substances.
They form new substances.
They involve heat.
They involve heat.
They are reversible.
They are reversible.
They include shifts in the phase of matter.
Chemical changes involve the formation of new substances, while physical changes do not.
Which
Please provide the options for the question.
How does a balanced chemical equation demonstrate the Law of Conservation of Mass?(1 point)
Responses
it shows that only physical changes follow the Law of Conservation of Mass
it shows that only physical changes follow the Law of Conservation of Mass
it shows that all compounds remain bonded after the reaction
it shows that all compounds remain bonded after the reaction
it shows that the properties of the elements stay the same after the reaction
it shows that the properties of the elements stay the same after the reaction
it shows that no atoms have been gained or lost during the reaction
A balanced chemical equation demonstrates the Law of Conservation of Mass by showing that no atoms have been gained or lost during the reaction.
How does a balanced chemical equation demonstrate the Law of Conservation of Mass?(1 point)
Responses
A.it shows that only physical changes follow the Law of Conservation of Mass
B.it shows that all compounds remain bonded after the reaction
C.it shows that the properties of the elements stay the same after the reaction
D.it shows that no atoms have been gained or lost during the reaction
D. It shows that no atoms have been gained or lost during the reaction.
If the total mass of the reactants is 58.44 amu, what will be the total mass of the products?
(1 point)
Responses
116.88 amu
116.88 amu
60 amu
60 amu
29.22 amu
29.22 amu
58.44 amu
To determine the total mass of the products, we need more information about the specific reaction and the mass of the products formed. The question does not provide any information about the reaction or the products, so we cannot determine the total mass of the products. Therefore, the correct answer is not given in the options provided.
If the total mass of the reactants is 58.44 amu, what will be the total mass of the products?
(1 point)
Responses
A.116.88 amu
B.60 amu
C.29.22 amu
D.58.44 amu
The total mass of the products cannot be determined solely based on the information provided. It depends on the specific reaction and the masses of the products formed. Therefore, the correct answer is not given in the options provided.
Which answer
Apologies for any confusion. Given the options provided, the correct answer would be D. 58.44 amu.
How does a balanced chemical equation demonstrate the Law of Conservation of Mass?(1 point)
Responses
A.it shows that only physical changes follow the Law of Conservation of Mass
K.it shows that all compounds remain bonded after the reaction
B.it shows that the properties of the elements stay the same after the reaction
C.it shows that no atoms have been gained or lost during the reaction
C. It shows that no atoms have been gained or lost during the reaction.
Matter Interactions Unit Test
10 of 1310 of 13 Items
Question
One molecule of bromine (Br2) and two molecules of potassium chloride (KCl) combine in a reaction. How many atoms are in the products?(1 point)
Responses
four
four
two
two
six
six
three
To determine the number of atoms in the products, we need to calculate the number of atoms in each reactant molecule and then add them together.
In the reactant bromine (Br2), there are 2 bromine atoms.
In the reactant potassium chloride (KCl), there is 1 potassium atom and 1 chlorine atom per molecule. Since we have 2 molecules of potassium chloride, we have a total of 2 potassium atoms and 2 chlorine atoms.
Adding these together, we have 2 bromine atoms + 2 potassium atoms + 2 chlorine atoms = 6 atoms in the products.
Therefore, the correct answer is: six.
Which of the following can be added to the products to balance the equation?
(1 point)
Responses
H2
H 2
O2
O 2
CH2OH
CH 2 OH
H2O
To determine which of the options can be added to balance the equation, we need to analyze the equation and check if any of the reactants or products are missing.
The equation in question is not provided, so we cannot determine which substance should be added to balance it. Therefore, the correct answer cannot be determined with the information given in the question.
A.H2
B.O2
C.CH2OH
D.
H2O