2 grams of potassium (K) reacts with 5 grams of Oxygen (O). According to the Law of Conservation of Mass, how many grams of potassium oxide (K2O) will be produced? (1 point)
Responses
7 grams
7 grams
10 grams
10 grams
5 grams
5 grams
2 grams
To determine how many grams of potassium oxide (K2O) will be produced, we need to calculate the molar masses of the reactants and products involved in the reaction.
First, let's find the molar mass of potassium (K). The atomic mass of potassium is approximately 39.1 grams per mole.
Next, let's find the molar mass of oxygen (O). The atomic mass of oxygen is approximately 16.0 grams per mole.
Using the given amounts, we can calculate the moles of potassium and oxygen by dividing their masses by their molar masses.
For potassium:
Moles of K = 2 grams / 39.1 grams/mol ≈ 0.051 mol
For oxygen:
Moles of O = 5 grams / 16.0 grams/mol ≈ 0.313 mol
The balanced chemical equation for the reaction between potassium and oxygen to form potassium oxide is:
4K + O2 → 2K2O
From the balanced equation, we can see that 4 moles of potassium react with 1 mole of oxygen to produce 2 moles of potassium oxide.
Now, let's determine the limiting reactant. The limiting reactant is the one that is completely consumed during the reaction and determines the amount of product that can be formed. To do this, we compare the mole ratios of the reactants.
The mole ratio between potassium and oxygen is 4:1, which means that for every 4 moles of potassium, we need 1 mole of oxygen. However, we have 0.051 moles of potassium and 0.313 moles of oxygen.
Since we have less moles of potassium than what is required in the reaction, potassium is the limiting reactant.
To find the moles of potassium oxide produced, we use the mole ratio between potassium and potassium oxide, which is 4:2. This means that for every 4 moles of potassium, we produce 2 moles of potassium oxide.
Moles of K2O produced = (0.051 mol K) x (2 mol K2O / 4 mol K) = 0.051 x 2 / 4 = 0.0255 mol K2O
Finally, we can calculate the mass of potassium oxide produced by multiplying the moles of K2O by its molar mass.
Mass of K2O = (0.0255 mol K2O) x (94.2 grams/mol K2O) ≈ 2.4 grams
Therefore, approximately 2.4 grams of potassium oxide (K2O) will be produced according to the Law of Conservation of Mass.
Which statement is true regarding a chemical reaction?(1 point)
Responses
Even if the total number of atoms changes, mass may not be conserved in the reaction.
Even if the total number of atoms changes, mass may not be conserved in the reaction.
The total number of atoms does not change, so mass is conserved in the reaction.
The total number of atoms does not change, so mass is conserved in the reaction.
The total number of atoms changes, so mass is conserved in the reaction.
The total number of atoms changes, so mass is conserved in the reaction.
Even if the total number of atoms does not change, mass may not be conserved in the reaction.
The statement that is true regarding a chemical reaction is:
The total number of atoms does not change, so mass is conserved in the reaction.
Use the equation and the table to answer the question.
FeCl3 + 3H2O → Fe(OH)3 + 3HCl
Element Mass of an Atom (amu)
Fe 56
Cl 35
H 1
O 16
Iron chloride and water react according to the equation shown. The table shows the atomic masses of the elements involved in the reaction. What is the total mass of the reactants?
(1 point)
Responses
179 amu
179 amu
215 amu
215 amu
108 amu
108 amu
161 amu
To calculate the total mass of the reactants, we need to add up the masses of all the individual atoms in the reactant molecules.
In FeCl3, there is 1 iron atom (Fe) with a mass of 56 amu, and 3 chlorine atoms (Cl) with a mass of 35 amu each. Therefore, the total mass of FeCl3 is:
1 iron atom (Fe) + 3 chlorine atoms (Cl) = 56 amu + (3 * 35 amu) = 56 amu + 105 amu = 161 amu
In 3H2O, there are 6 hydrogen atoms (H) with a mass of 1 amu each, and 3 oxygen atoms (O) with a mass of 16 amu each. Therefore, the total mass of 3H2O is:
6 hydrogen atoms (H) + 3 oxygen atoms (O) = (6 * 1 amu) + (3 * 16 amu) = 6 amu + 48 amu = 54 amu
To find the total mass of the reactants, we add the mass of FeCl3 and the mass of 3H2O:
Total mass of the reactants = mass of FeCl3 + mass of 3H2O = 161 amu + 54 amu = 215 amu
Therefore, the total mass of the reactants is 215 amu.
10 grams
Which of the following equations demonstrates the Law of Conservation of Mass? (1 point)
Responses
CH4+O2→C+2H2O
CH4+O2→CO2+H2O
CH4+O2→CO2+HO
CH+O2→CO2+H2O
The equation that demonstrates the Law of Conservation of Mass is:
CH4 + 2O2 → CO2 + 2H2O
This equation shows that the number of atoms on both sides of the reaction is balanced. The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction, so the total number of atoms on both sides of the equation should be the same.
To determine the mass of potassium oxide (K2O) produced, we must first calculate the number of moles of potassium (K) and oxygen (O) in the reaction.
The molar mass of potassium (K) is 39.10 g/mol, while the molar mass of oxygen (O) is 16.00 g/mol.
First, we need to find the number of moles of each element present.
For potassium (K):
Number of moles = mass / molar mass
Number of moles = 2 g / 39.10 g/mol
Number of moles = 0.051 moles
For oxygen (O):
Number of moles = mass / molar mass
Number of moles = 5 g / 16.00 g/mol
Number of moles = 0.313 moles
According to the balanced chemical equation for the reaction:
2K + O2 -> 2K2O
The stoichiometric ratio between potassium (K) and potassium oxide (K2O) is 2:2. Therefore, for every 2 moles of potassium, we get 2 moles of potassium oxide.
Since we have 0.051 moles of potassium (K) from our calculation, we can say that we will produce 0.051 moles of potassium oxide (K2O).
Finally, we can calculate the mass of potassium oxide (K2O) using the number of moles and molar mass.
Mass of K2O = number of moles * molar mass
Mass of K2O = 0.051 mol * (2 mol K2O / 1 mol K2O) * (39.10 g/mol)
Mass of K2O = 4.001 g
Therefore, 2 grams of potassium (K) will react with 5 grams of oxygen (O) to produce 4.001 grams of potassium oxide (K2O) according to the Law of Conservation of Mass.
In which chemical equation is the number of atoms in the reactants the same as the number of atoms in the products?(1 point)
Responses
Zn + 2HCl → H2 + ZnCl2
Zn + 2HCl → H 2 + ZnCl 2
Li2CO3 → LiO + CO2
Li 2 CO 3 → LiO + CO 2
CO2 + H2O → CH2OH + O2
CO 2 + H 2 O → CH 2 OH + O 2
CH4 + O2 → CO2 + 2H2O