How many substances does a pure piece of matter contain?

A. 0

B. 1

C. 2

D. 3

Infrequent participation in physical activity can lead to a. high blood pressure during exercise b. muscle strain and soreness after exercise c. extra calories burned during exercise d. low heart rate after exercise

Which of the answer choices accurately describes a trend that occurs when moving left to right across periods? (Select all that apply.) reactivity increases atomic radius increases atomic mass increases valence electrons decrease

4.0 L of He (g), 6.0 L of N2 (g), and 10. L of Ar (g), all at 0°C and 1.0 atm, are pumped into an evacuated 8.0 L rigid container, the final pressure in the container at 0°C is

28. Explain the difference between the processes of melting and freezing?

What percentage of greenhouse gas emission from burning fossil fuels remain in the atmosphere?

A flask contains 4.4g of carbon dioxide gas. calculate how many moles CO2 gas does it contains?

What defines a mixture? A) A mixture contains different substances that are chemically combined. B) A mixture contains different substances that are not chemically combined and can be broken down into its basic substances through physical means.

How much does 5 gallons of water weigh?

Calculate the percent by mass sulfur in sulfuric acid, h2so4.

4. What electrons are involved in chemical bonding?