Question
Use the chemical reaction to answer the question.
CaCO3→CO2+CaO
A scientist heats 30 grams of calcium carbonate (CaCO3
) in the chemical reaction shown. What is the total mass of the products?
(1 point)
Responses
15 grams
15 grams
60 grams
60 grams
30 grams
30 grams
10 grams
The correct answer is 60 grams. The total mass of the products is equal to the sum of the masses of carbon dioxide (CO2) and calcium oxide (CaO). Since the chemical reaction does not specify any other reactants or products, we assume that the entire 30 grams of calcium carbonate is converted into these products. Therefore, the mass of carbon dioxide and calcium oxide would be equal to 30 grams each, resulting in a total mass of 60 grams.
Which is most likely to occur during a chemical reaction?(1 point)
Responses
New atoms are created.
New atoms are created.
The original substance maintains its properties.
The original substance maintains its properties.
Mass is conserved.
Mass is conserved.
Atoms of the original substance are lost.
The correct answer is "Mass is conserved." During a chemical reaction, mass is conserved, meaning that the total mass of the reactants is equal to the total mass of the products. Atoms are not created or lost during a chemical reaction, and while the properties of the substances may change, the original substance does not maintain its properties.
Use the chemical reaction to answer the question.
NaHCO3+HC2H3O2→NaC2H3O2+H2O+CO2
A student mixes baking soda (NaHCO3
) and acetic acid (HC2H3O2
) to produce a chemical reaction shown. Which statement about the reaction is correct?
(1 point)
Responses
There are more H atoms after the reaction.
There are more H atoms after the reaction.
Some atoms gain mass after the reaction.
Some atoms gain mass after the reaction.
The atoms of the reactants are regrouped during the reaction.
The atoms of the reactants are regrouped during the reaction.
Atoms of Na are destroyed during the reaction.
The correct answer is "The atoms of the reactants are regrouped during the reaction." In a chemical reaction, the atoms of the reactants are rearranged to form the products. In this particular reaction, the atoms of sodium (Na), hydrogen (H), carbon (C), and oxygen (O) are regrouped to form new compounds. There is no destruction of Na atoms or an increase in the number of H atoms or mass.
Use the chemical reaction to answer the question.
2H2+O2→2H2O
There are four atoms of hydrogen ( H
) before the reaction. How many atoms of hydrogen are present after the reaction?
(1 point)
Responses
8
8
5
5
2
2
4
The correct answer is 4.
In the given chemical reaction, we have 2 molecules of hydrogen (H2) as reactants. Each H2 molecule contains two hydrogen atoms. Therefore, the total number of hydrogen atoms before the reaction is 2 (H2 molecules) * 2 (hydrogen atoms per molecule) = 4 hydrogen atoms.
In the products of the reaction, we have 2 molecules of water (H2O). Each water molecule contains 2 hydrogen atoms. Therefore, the total number of hydrogen atoms after the reaction is 2 (H2O molecules) * 2 (hydrogen atoms per water molecule) = 4 hydrogen atoms.
Hence, there are still 4 atoms of hydrogen present after the reaction.
Use the chemical reaction to answer the question.
H2O2→H2O+O2
Which equation for this reaction demonstrates the Law of Conservation of Mass?
(1 point)
Responses
2H2O2→2H2O+2O2
2 cap h sub 2 cap o sub 2 rightarrow 2 cap h sub 2 cap o plus 2 cap o sub 2
2H2O2→2H2O+O2
2 cap h sub 2 cap o sub 2 rightarrow 2 cap h sub 2 cap o plus cap o sub 2
H2O2→H2O+O2
H2O2→H2O+O2
H2O2→H2O+2O2
The correct equation that demonstrates the Law of Conservation of Mass is:
2H2O2→2H2O+O2
This equation shows that 2 molecules of hydrogen peroxide (H2O2) react to form 2 molecules of water (H2O) and 1 molecule of oxygen (O2). The balanced equation ensures that the mass of the reactants is equal to the mass of the products, thereby conserving mass.
Flies are scavengers and tend to break down dead organisms. Based on this information, what is a plant characteristic that would best attract flies?
flowers that are brightly colored
flowers that emit a sweet odor
flowers that are light colored
flowers that emit a rotten odor