Q: Which of the following is the correct formula for converting Celsius to Kelvin?

$$K = (\text{temp. in Celsius}) + 273$$

Q: What is the correct formula for the heat equation used to calculate the amount of heat absorbed or released?

$$q = m \times \Delta T \times SH$$

Question 1

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the components do not have a uniform composition and appear as separate regions.

Question 2

A student measures the mass of a sample as 0.00450 g. How many significant figures are in this measurement?

Accepted Answer

3

Question 3

Which of the following is the correct formula for converting Celsius to Kelvin?

Accepted Answer

$$K = (	ext{temp. in Celsius}) + 273$$

Question 4

A sample of orange light has a wavelength of $$6.3 	imes 10$$^{-7}$$ m. What is its wavelength in nanometers (nm)?

Accepted Answer

630 nm

Question 5

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 6

Which of the following is a chemical change?

Accepted Answer

Burning wood in a fireplace.

Question 7

What is the correct formula for the heat equation used to calculate the amount of heat absorbed or released?

Accepted Answer

$$q = m 	imes \Delta T 	imes SH$$

Question 8

Which of the following best describes a cation?

Accepted Answer

A positively charged ion formed by losing electrons.

Question 9

A compound is formed when:

Accepted Answer

Two or more elements are chemically combined in a fixed ratio.

Question 10

Which of the following is the correct relationship between the speed of light $$(c)$$, wavelength $$(\lambda)$$, and frequency $$(
u)$$?

Accepted Answer

$$c = \lambda 	imes 
u$$

Question 11

Which of the following elements is a noble gas?

Accepted Answer

Neon

Question 12

What is the name of the compound with the formula $$PbSO_4$$?

Accepted Answer

Lead(II) sulfate

Question 13

Which of the following statements about density is correct?

Accepted Answer

Objects that float in water are less dense than water.

Question 14

Which group on the periodic table contains the alkali metals?

Accepted Answer

Group 1A (1)

Question 15

A student is asked to calculate the atomic mass of an element with two isotopes: 40% isotope A (mass 10 amu) and 60% isotope B (mass 12 amu). What is the atomic mass?

Accepted Answer

$$10.8$$ amu

Question 16

Which of the following is a correct example of scientific notation?

Accepted Answer

$$2.4 	imes 10^3$

Question 17

Which of the following best describes a physical property?

Accepted Answer

The melting point of ice.

Question 18

What is the correct name for the ionic compound $$Mg_3P_2$$?

Accepted Answer

Magnesium phosphide

Question 19

Which of the following is a homogeneous mixture?

Accepted Answer

Air (a mixture of oxygen and nitrogen gases).

Question 20

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons are the electrons in the outermost energy level.

Introductory Chemistry: Core Concepts and Foundations

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