The sugar ribose consists of 40.00 % C, 6.714 % H, and 53.29 % O. What is its empirical formula? Its molecular mass is 150.1 g/mol. What is its molecular formula?

EF CH2O   MF   C5H10O2

Explanation:

C40/12H6.7/1 O53.29/16  =  C3.33H6.7O3.33

Divide by 3.33   C1H2O1    empirical mass  = 30g/mol

Mol mass 150.1 g/mol  5 times more

multiply empirical formula by 5

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.