Question

Can someone please help me with these questions?
1 (7). Rank the following in order of increasing radius based on their positions on the periodic table: S, S-2, Cl
a. S, S-2, Cl
b. S-2, Cl, S
c. Cl, S, S-2
d. Cl, S-2, S
e. S, Cl, S-2

6 (16). Methane burns in oxygen according to the following equation:
CH4(g) + 2O2(g) „³ CO2(g) + 2H2O
What is the mass of CO2 produced when 3.4 grams O2 reacts according to the above equation?
a. 4.7g
b. 4.9g
c. 2.3g
d. 9.4g
e. 0.74g

Answer 1

For 1, generally the radius decreases as one moves from the left to the right in the periodic table. Adding electrons to the outer shell (as in S^-2) usually increases the size disproportionately because the electrons are repelling one another.

For #2, make sure the equation is balanced.
Convert 3.4 grams O2 to moles O2. moles = grams/molar mass.
Using the coefficients in the balanced equation, convert moles O2 to moles of CO2.
Convert moles CO2 to grams. grams = moles x molar mass.