Chemistry Quiz For 11 Year Old

1. Potassium is a chemical element with which symbol?

P

T

S

K

Potassium is a chemical element that is represented by the symbol K. This symbol is derived from the Latin word "kalium." Potassium is an essential mineral for the human body and is involved in various physiological processes. It is commonly found in bananas, potatoes, and other fruits and vegetables.

Explanation

Potassium is a chemical element that is represented by the symbol K. This symbol is derived from the Latin word "kalium." Potassium is an essential mineral for the human body and is involved in various physiological processes. It is commonly found in bananas, potatoes, and other fruits and vegetables.

2. What is the electron configuration for Sulphur?

(2, 8, 7)

(2, 6, 5)

(2, 8, 6)

(2, 6, 8)

The electron configuration for an atom indicates the arrangement of electrons in its energy levels. Sulphur has an atomic number of 16, meaning it has 16 electrons. The electron configuration of Sulphur is 1s2 2s2 2p6 3s2 3p4. This can be simplified as (2, 8, 6), which represents the number of electrons in each energy level.

Explanation

The electron configuration for an atom indicates the arrangement of electrons in its energy levels. Sulphur has an atomic number of 16, meaning it has 16 electrons. The electron configuration of Sulphur is 1s2 2s2 2p6 3s2 3p4. This can be simplified as (2, 8, 6), which represents the number of electrons in each energy level.

3. What are the coefficients for the following equation when it is balanced?
___SiO₂ + ___HF --> ___SiF₄ + ___H₂O

2, 3, 2, 2

1, 4, 1, 2

2, 4, 1, 3

1, 3, 2, 3

The balanced equation is 1 SiO2 + 4 HF -> 1 SiF4 + 2 H2O. This means that for every 1 molecule of SiO2, 4 molecules of HF are required to produce 1 molecule of SiF4 and 2 molecules of H2O.

Explanation

The balanced equation is 1 SiO2 + 4 HF -> 1 SiF4 + 2 H2O. This means that for every 1 molecule of SiO2, 4 molecules of HF are required to produce 1 molecule of SiF4 and 2 molecules of H2O.

4. How is a mixture different from a compound?

Particles of a mixture are combined chemically.

Components of a mixture can be separated by physical means.

Components of a mixture can only be separated chemically.

The composition of a mixture may be constant.

A mixture is different from a compound because the components of a mixture can be separated by physical means. In a mixture, the different substances are combined together but they retain their individual properties and can be easily separated. This is in contrast to a compound where the elements are chemically bonded together and cannot be separated by physical means. The ability to separate the components of a mixture is a key characteristic that distinguishes it from a compound.

Explanation

A mixture is different from a compound because the components of a mixture can be separated by physical means. In a mixture, the different substances are combined together but they retain their individual properties and can be easily separated. This is in contrast to a compound where the elements are chemically bonded together and cannot be separated by physical means. The ability to separate the components of a mixture is a key characteristic that distinguishes it from a compound.

5. Balance the following:
___BF₃ + ___Li₂SO₃ + ___B₂(SO₃)₃ + ___LiF

What will the coefficients be for the balanced reaction?

2, 4, 1, 5

1, 2, 1, 3

2, 3, 1, 6

1, 3, 2, 6

The balanced reaction for the given equation is 2BF3 + 3Li2SO3 + B2(SO3)3 + 6LiF. This is determined by ensuring that the number of atoms of each element is the same on both sides of the equation. In this case, by adjusting the coefficients, we can see that there are 2 boron (B) atoms, 6 fluorine (F) atoms, 3 lithium (Li) atoms, and 1 sulfur (S) atom on both sides of the equation. Therefore, the coefficients for the balanced reaction are 2, 3, 1, and 6.

Explanation

The balanced reaction for the given equation is 2BF3 + 3Li2SO3 + B2(SO3)3 + 6LiF. This is determined by ensuring that the number of atoms of each element is the same on both sides of the equation. In this case, by adjusting the coefficients, we can see that there are 2 boron (B) atoms, 6 fluorine (F) atoms, 3 lithium (Li) atoms, and 1 sulfur (S) atom on both sides of the equation. Therefore, the coefficients for the balanced reaction are 2, 3, 1, and 6.

6. Name this compound:

Hint: this is the reaction between a non-metal and a non-metal

Nitrogen oxide

Dinitrogen tetroxide

Tetraoxygen dinitride

Oxygen nitride

Dinitrogen tetroxide is the correct answer because it is a compound formed by the reaction between two non-metals, nitrogen and oxygen. The prefix "di-" indicates that there are two nitrogen atoms, and the name "tetroxide" indicates that there are four oxygen atoms. Therefore, the compound is correctly named as dinitrogen tetroxide.

Explanation

Dinitrogen tetroxide is the correct answer because it is a compound formed by the reaction between two non-metals, nitrogen and oxygen. The prefix "di-" indicates that there are two nitrogen atoms, and the name "tetroxide" indicates that there are four oxygen atoms. Therefore, the compound is correctly named as dinitrogen tetroxide.

7. How many neutrons are in potassium-40?

19

40

21

27

Potassium-40 is an isotope of potassium, which means it has the same number of protons but a different number of neutrons. The atomic number of potassium is 19, indicating that it has 19 protons. The atomic mass of potassium-40 is 40, so subtracting the number of protons (19) from the atomic mass gives us the number of neutrons. Therefore, there are 21 neutrons in potassium-40.

Explanation

Potassium-40 is an isotope of potassium, which means it has the same number of protons but a different number of neutrons. The atomic number of potassium is 19, indicating that it has 19 protons. The atomic mass of potassium-40 is 40, so subtracting the number of protons (19) from the atomic mass gives us the number of neutrons. Therefore, there are 21 neutrons in potassium-40.

8. If a certain mixture is homogeneous, you would properly conclude that the physical properties and the composition are:

Vary smoothly from top to bottom of the sample

Are different from one part of the sample to another

Are the same in every small volume element of the sample

None of these

If a certain mixture is homogeneous, it means that the components are evenly distributed throughout the sample. This implies that the physical properties and composition of the mixture will be the same in every small volume element of the sample. Therefore, the correct answer is "are the same in every small volume element of the sample."

Explanation

If a certain mixture is homogeneous, it means that the components are evenly distributed throughout the sample. This implies that the physical properties and composition of the mixture will be the same in every small volume element of the sample. Therefore, the correct answer is "are the same in every small volume element of the sample."

9. What is the name for the compound CuOH?

Copper hydroxide

Copper(I) hydrogen oxide

Copper(I) hydroxide

Copper hydrogen oxide

The correct answer is Copper(I) hydroxide. This compound is named using the Stock system for naming compounds with transition metals. In this system, the Roman numeral in parentheses indicates the oxidation state of the metal ion, which in this case is copper(I) or cuprous. The hydroxide ion (OH-) is a polyatomic ion, so its name remains unchanged. Therefore, the compound is named Copper(I) hydroxide.

Explanation

The correct answer is Copper(I) hydroxide. This compound is named using the Stock system for naming compounds with transition metals. In this system, the Roman numeral in parentheses indicates the oxidation state of the metal ion, which in this case is copper(I) or cuprous. The hydroxide ion (OH-) is a polyatomic ion, so its name remains unchanged. Therefore, the compound is named Copper(I) hydroxide.

10. What is the most correct Lewis Diagram for Helium?

Potassium-40 is an isotope of potassium, which means it has the same number of protons but a different number of neutrons. The atomic number of potassium is 19, indicating that it has 19 protons. The atomic mass of potassium-40 is 40, so subtracting the number of protons (19) from the atomic mass gives us the number of neutrons. Therefore, there are 21 neutrons in potassium-40.

Explanation

Potassium-40 is an isotope of potassium, which means it has the same number of protons but a different number of neutrons. The atomic number of potassium is 19, indicating that it has 19 protons. The atomic mass of potassium-40 is 40, so subtracting the number of protons (19) from the atomic mass gives us the number of neutrons. Therefore, there are 21 neutrons in potassium-40.