Q: What is the correct formula for calculating the percentage of a component in a mixture?

$$\text{Percentage} = \dfrac{\text{Component}}{\text{Total}} \times 100$$

Q: A sample contains 11.6 g of lead in a total mass of 11.7 g. What is the percentage of lead in the sample?

$$\dfrac{11.6}{11.7} \times 100 = 99.1\%$$

Question 1

Which statement best describes the difference between substances with the same chemical composition but different functions, such as toothpaste and soap?

Accepted Answer

They have the same chemical composition and properties, but their functions differ due to formulation and intended use.

Question 2

What is the correct formula for calculating the percentage of a component in a mixture?

Accepted Answer

$$	ext{Percentage} = \dfrac{	ext{Component}}{	ext{Total}} 	imes 100$$

Question 3

A sample contains 11.6 g of lead in a total mass of 11.7 g. What is the percentage of lead in the sample?

Accepted Answer

$$\dfrac{11.6}{11.7} 	imes 100 = 99.1\%$$

Question 4

Which of the following is the correct scientific notation for the number 0.00056?

Accepted Answer

$$5.6 	imes 10$$^{-4}$$

Question 5

If the slope of a line is calculated using the formula $$	ext{Slope} = \dfrac{	ext{Rise}}{	ext{Run}}$$, what is the slope for a line passing through the points (6, 23.3) and (50, 0)?

Accepted Answer

$$\dfrac{0 - 23.3}{50 - 6} = -0.53$$

Question 6

Which of the following statements about the periodic table is correct?

Accepted Answer

Groups are arranged vertically and periods are arranged horizontally.

Question 7

Which group on the periodic table contains the noble gases?

Accepted Answer

Group 8A

Question 8

Which characteristic is NOT typical of metals?

Accepted Answer

Brittle and poor conductor

Question 9

According to Dalton's atomic theory, which statement is true?

Accepted Answer

Atoms of the same element are identical in mass and properties.

Question 10

Which experiment led to the discovery of the electron?

Accepted Answer

Thomson's cathode ray experiment

Question 11

What is the relationship between energy and wavelength in electromagnetic radiation?

Accepted Answer

Higher energy corresponds to shorter wavelengths.

Question 12

Which subatomic particle determines the atomic number of an element?

Accepted Answer

Proton

Question 13

An atom has 11 protons, 12 neutrons, and 10 electrons. What is its charge and what type of ion is it?

Accepted Answer

Charge: +1, Cation

Question 14

Which of the following is true about isotopes?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 15

What is the mass number of an atom with 20 protons and 22 neutrons?

Accepted Answer

$$42$$

Question 16

Which of the following best describes a metalloid?

Accepted Answer

A substance with properties intermediate between metals and nonmetals.

Question 17

If an atom has a positive charge, what does this indicate about its subatomic particles?

Accepted Answer

It has more protons than electrons.

Question 18

Which of the following is the correct equation for a line with slope $$m$$ and $$y-$$intercept $$b$$?

Accepted Answer

$$y = mx + b$$

Question 19

Which of the following is NOT a feature of atomic number ($$Z$$)?

Accepted Answer

It is the sum of protons and neutrons.

Question 20

A neutral atom of carbon has 6 protons, 6 neutrons, and 6 electrons. What is its atomic number and mass number?

Accepted Answer

Atomic number: $$6$$, Mass number: $$12$$

General Chemistry 1: Foundations, Atomic Structure, and the Periodic Table

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