CE Chemistry Review Chapter 2
1. Why is MgO the symbol for magnesium oxide rather than MGO?
2. What is the meaning of the 2 in H2SO4?
3. Find the molecular weight of CaCl2 in u or amu.
4. Using whole numbers, find the molecular weight of Al(OH)3.
5. Describe and compare the mass, charge and location of protons, neutrons, and electrons.
6. How many electrons are in a neutral atom of calcium-41, ( 41𝐶𝑎)?
7. What charge do atoms have and why? (explain)
8. How are isotopes the same? How are isotopes different?
9. How is Thorium-232 different from Thorium-230?
10. How many protons are in the nucleus of 25𝑀𝑔 atom?
11. How many neutrons are in the nucleus of 25𝑀𝑔 atom?
12. What is the mass number of 25𝑀𝑔?
13. Naturally occurring copper (Cu) has 2 isotopes, Cu-63 and Cu-65. Use the periodic table and
determine which isotope is present in the larger percentage.
14. What mass of aluminum (Al) in grams contains the same number of atoms as 83.80 g of Kr?
15. One Avogadro’s number of silver (Ag) atoms would weigh?
16. How many atoms are contained in a sample of Fluorine (F) that weighs 18.999 g?
17. Which has the largest mass? 5.0 moles Li, 3.1 mole H2O, 2.0 moles C2H4, or 2.5 moles NH3
18. How many boron (B) atoms are contained in 10.2g sample of boron?
19. How many moles of hydrogen atoms are in 1 mole of H2O?
20. How many hydrogen atoms are in 1.00 moles CH4?
21. Calculate the weight percentage of hydrogen in methane, CH4?
22. What is the percent weight of hydrogen in urea, CN2H4O?
23. How many carbon atoms are contained in 5.50g of propane, C3H8 ?
24. How many grams of calcium is contained in 17.9g of Ca(OH)2?
25. The weight percentage of phosphorus (P) in H3PO4 is?
26. How many neutrons are in an atom that has a mass number of 55 and contains 25 protons?
27. Determine the number of electrons and protons in element Mo.
28. Write the formula of a compound consisting of 1 sodium atom, 1 nitrogen atom and 3 oxygen
atoms.
29. How many electrons are found in an antimony (Sb) atom?
30. What is the molar mass of Ca3(PO4)2?
31. Th-230 is one form of thorium. How many protons, neutrons and electrons does one atom of
this isotope consists of?
32. What is the mass of oxygen found in 1 mole of H2C2O4?
33. A new element consists of 2 isotopes, 31𝑋 (𝑚𝑎𝑠𝑠 = 30.964 𝑢)𝑐𝑜𝑚𝑝𝑟𝑖𝑠𝑒𝑠 25.357% of the total.
The 2nd isotope, 29𝑋 (𝑚𝑎𝑠𝑠 = 29.012 𝑢)𝑎𝑐𝑐𝑜𝑢𝑛𝑡𝑠 𝑓𝑜𝑟 𝑡ℎ𝑒 𝑟𝑒𝑠𝑡. What will be the average atomic
mass for the new element?