Which of these is an example of a physical change?
a)sugar dissolving in warm water
b)iron rusting in the presence of moist air
c)wood burning in the presence of oxygen
d)baking soda reacting with acid to form a gas

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture

What effect does a decrease in temperature have on the overall rate of a chemical reaction? a decrease in temperature decreases . the reaction rate will

In the space, show a correct numerical setup for calculating the number of moles of co2 present in 11 grams of co2