Scientists are often interested in knowing the molar heat of combustion – the heat released during the combustion of one mole of a substance. Use the Periodic Table to find molar masses.

How many moles of ethanol are present in the sample?

Which statement best describes how atoms combine to form sodium chloride (nacl)? a. a positively charged sodium ion and a positively charged chlorine ion form an covalent bond. b. a positively charged sodium ion and a negatively charged chlorine ion form an covalent bond. c. a positively charged sodium ion and a positively charged chlorine ion form an ionic bond. d. a positively charged sodium ion and a negatively charged chlorine ion form an ionic bond.

Different isotopes indicate that an element will have different numbers of

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