1. SCIENCE AND TECHNOLOGY 111
(Chemistry)
SEMI FINAL
Encircle the letter of the correct answer.
1.The correct coefficients for the equation KCLO3 → KCL + O2 are
a. 2, 2, 3 b. 3, 2, 2 c. 2, 3, 2 d. 2, 1, 3
2. Given Al (OH)3 → Al2 O3 + H2O. Which of the ff set of coefficients is correct to balance the
given decomposition reaction.
a. 2, 1, 3 b. 2, 3, 1 c. 1,2,3 d. 3, 1, 2
3. Balancing a chemical equation involves
a. adjusting the subscripts
b. adjusting the coefficients.
c. adjusting both subscripts and coefficients.
d. adjusting the masses of reactants and products.
4. NH3 + HCL → NH4 Cl is classified as
a. synthesis b. analysis c. single replacement reaction
d. double replacement reaction
5.2Al + 6HCL → 2AlCl3 + 3H2 is classified as
a. synthesis b. analysis c. single replacement reaction
d. double replacement reaction
6. Which of the ff. is not correctly balanced?
a. N2 + 3H2 → 2NH3
b. Zn +H2 SO4 → ZnSO4 + H2
c. 2Hl → H2 + I2
d. MgCl2 + 2NaOH → NaCl + Mg(OH)2
7. Which of the following is correctly balanced ?
a. Li + O2 → Li2O
b. Cl2 + Kl → KCl + I2
c. CaCO3 → CaO + CO2
d. Mg + HCL → MgCl2 + H2
8. When the equation NH3 + O2 → HNO3 + H2O is completely balanced using smallest whole
numbers, the coefficient of O2 is
a. 1 b. 2 c. 3 d. 4
9. When the equation : ___Al2 ( SO4)3 + ___ZnCl2 → ___AlCl3 + __ZnSO4 is correctly balanced
using the smallest whole – number coefficients, the sum of all the coefficients is
a. 4 b. 5 c. 8 d.9
10. When the equation __H2 + Fe3O4 → __ Fe + __H2O is completely balanced using smallest
whole-number coefficients, the coefficients of H2 is
a. 1 b. 2 c. 3 d. 4
11. The formula that indicates the total number of atoms of the elements in a compound is the
a. empirical formula b. molecular formula c. structural formula d. simplest formula
12.The formula mass of limewater, Ca(OH)2, when Ca= 40.1, O= 16.0, and H= 1.O is
a. 74.1 b. 57.1 c. 58.1 d. 72.1
13. In chemical reaction, the mass of the products
a. is less than the mass of the reactants.
b. is greater than the mass of the reactants.
c. is equal to the mass of the reactants.
d. has no relationship to the mass of the reactants.
14. The molar mass of camphor , C10H16O, when C= 12.O, O= 16.O, and H = 1.O is
a.136.0 g b. 152.0 g c. 150.0 g d. 160.0 g
15. Calculate the number of grams present in 0.65 mole of ammonium carbonate, (NH4)2 CO3, a
substance found in baking powder? (N= 14.O)
a. 62 g b .65 g c. 72 g d. 75 g
16.Which of the ff. is not a molecular formula?
a. HC2H3O2 b. CHO c. NaOH d. Na2CO3 . 10 H2O
For question 17-19, please refer to the chemical equation below.
2NO+ O2→ 2NO2

2. 17. How many molecules of NO2 can be formed using 2 molecules of NO?
a.1 b.2 c. 3 d. 4
18. How many moles of nitrogen monoxide are needed to give 4 moles of NO2?
a.1 b. 2 c.3 d.4
19. How many moles of oxygen atoms are there in 1 mole of oxygen molecules?
a.2 b.3 c. 4 d. 5
20. In any chemical reaction, the quantities that are preserved are
a. the number of moles and the volumes.
b. the number of molecules and the volume
c. the mass and number of atoms.
d. mass and moles
21. In the reaction 2C 2H6 + 7O2 → 4CO2 + 6H2O, the ratio of moles of C2H6 to moles of H2O is
a. 2:7 b. 1:2 c. 1:3 d. 3:1
22. According to Avogadro’s hyphothesis, equal volumes of all gases at the same temperature
and pressure have the same
a. mass b. number of particles c. density d.
none of the above
23. To change from moles of the substance given, to moles of the substance sought one uses
the
a. ratio of the molar masses of the two substances .
b. balanced equation coefficients for the substances.
c. subscripts in the formulas for the substances
d. all of the above
24. How many sulfur atoms are there in 96.3 g of sulfur?
a. 1 b. 3 c. 6 × 10 23 d. 1.8 × 1024
25. The number of molecules of nitrogen, N2, found in 500g of nitrogen gas is
a.1 b.5 c. 18 × 1023 d. 1× 1025
26. A compound is 26.58% potassium, 35.4 % chromium, and 38.02% oxygen. The empirical
formula of the compound is
a. KCrO7 b. K2CrO7 c. K2Cr2O7 d. KCr2O7
27 .When the vapor pressure of a liquid in an open container equals the atmospheric pressure,
the liquid will
a. boil b. crystallize c. freeze d. melt
28. As the temperature of a liquid increases , its vapor pressure
a. decreases b. increases c. remains the same d. decreases then increase
29. At what temperature does a water sample have the highest average kinetic energy?
a. 00C b. 1000C c. O K d. 100 K
30. The boiling point of water at standard pressure is
a. 0.00 K b. 100.0 K c. 273 K d. 373 K
Prepared by:
MARITES N. CAILING