Balancing Chemical Equations, My Science Skills

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AbuBakrShalabi

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1 / 20

In the balanced equation 2H₂ + O₂ → 2H₂O, what is the coefficient of hydrogen (H) on the product side?

3

2

1

4

2 / 20

Which statement best describes the law of conservation of energy?

The amount of energy released by a system must be more than that absorbed by the surrounding.

The total energy absorbed and released from a chemical reaction stays the same.

Energy can't be transferred between the system and the surroundings.

The total energy absorbed and released from a chemical reaction varies.

3 / 20

What is the Law of Conservation of Mass?

The total charge of a system must remain constant.

Matter can be neither created nor destroyed in a chemical reaction.

Energy can be neither created nor destroyed.

The total energy absorbed and released from a chemical reaction varies.

4 / 20

Why is it important to balance a chemical equation?

To make the equation look neat

To calculate the rate of reaction

To represent the Law of Conservation of Mass

To identify the reactants and products

5 / 20

What is the coefficient in a balanced chemical equation?

An element on the right side of the equation

An element on the left side of the equation

A small number written behind a chemical formula

A large number written in front of a chemical formula

6 / 20

In the unbalanced equation: Fe + O₂ → FeO₃ how many Fe atoms are on the reactant side?

1

It depends on the amount of Fe used

2

There is no Fe in the equation

7 / 20

In a closed system undergoing a chemical reaction, the total mass of the reactants must be:

Equal to the total mass of the products.

Less than the total mass of the products.

Greater than the total mass of the products.

Unrelated to the total mass of the products.

8 / 20

A chemical reaction happens when ___________.

new bonds are formed to create complex compounds

existing bonds break and the atoms rearrange to form new bonds

new atoms are created in the products

existing atoms in the reactants are destroyed

9 / 20

When balancing an equation, you can:

None of the above

Change the chemical formulas of the reactants and products

Add or remove atoms from the equation

Change the coefficients in front of the formulas

10 / 20

If 5 grams of magnesium (Mg) react with oxygen (O₂) to form magnesium oxide (MgO), the total mass of the magnesium oxide produced will be:

More than 5 grams.

Exactly 5 grams.

Less than 5 grams.

Impossible to determine without knowing the amount of oxygen used.

11 / 20

Which of the following equations is balanced?

Fe + 2HCl → FeCl2 + H

C3H8 + 5O2 → 3CO2 + 4H2O

2Na + 2Cl2 → 2NaCl

H2 + O2 → H2O

12 / 20

When balancing an equation, you can change the subscripts in the chemical formulas.

True

False

13 / 20

What is the coefficient needed in front of O₂ to balance the following equation?

CH₄ + O₂ → CO₂ + 2H₂O

4

2

1

3

14 / 20

When balancing the equation Fe + S → FeS, what coefficient is needed in front of FeS?

3

It cannot be balanced.

2

1

15 / 20

What is the balanced equation for the reaction between methane (CH4) and oxygen (O2) to produce carbon dioxide (CO2) and water (H2O)?

CH4 + O2 → CO2 + 2H2O

CH4 + 2O2 → CO2 + 2H2O

CH4 + O2 → CO2 + H2O

CH4 + 2O2 → 2CO2 + H2O

16 / 20

In a balanced equation, the total number of atoms of each element must be the same on both sides of the reaction arrow.

True

False

17 / 20

What does balancing a chemical equation mean?

Making sure the number of atoms of each element is the same on both sides of the reaction arrow

Adding heat to a reaction

Replacing elements with different ones

Changing the names of the reactants and products

18 / 20

What are the missing coefficients for the chemical equation below?

P + O₂ → P₂O₅

2 , 2 , 5

2 , 5 , 4

1 , 3 , 4

4 , 5 , 2

19 / 20

In the balanced equation N₂ + 3H₂ → 2NH₃, how many atoms of hydrogen (H) are on the reactant side?

2

6

4

3

20 / 20

What are the missing coefficients for the chemical equation below?

Ag₂O → Ag + O₂

5 , 4 , 2

2 , 2 , 2

2 , 4 , 1

1 , 2 , 3

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