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
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.
Sure, I can help you with these questions.
1 (7). To rank the elements in order of increasing radius based on their positions on the periodic table (S, S-2, Cl), we need to consider the periodic trends. Atomic radius generally increases as you move down a group (vertical) and decreases as you move across a period (horizontal) from left to right.
Therefore, we can analyze the elements:
- Sulfur (S) is in the same group as Chlorine (Cl) but below it, so it has a greater atomic radius compared to Chlorine.
- Sulfur ion (S-2) has gained 2 extra electrons compared to Sulfur, causing it to have a larger radius than Sulfur.
- Chlorine (Cl) has the smallest atomic radius.
Based on this analysis, the correct order of increasing radius is: c. Cl, S, S-2.
6 (16). To find the mass of CO2 produced when 3.4 grams of O2 reacts according to the given balanced equation, we need to use stoichiometry.
First, determine the molar mass of O2 and CO2:
- O2 has a molar mass of 32 grams/mol (16 grams/mol x 2 atoms).
- CO2 has a molar mass of 44 grams/mol (12 grams/mol + 16 grams/mol x 2 atoms).
Next, calculate the mole ratio between O2 and CO2 from the balanced equation:
- From the balanced equation, we see that 2 moles of O2 react to produce 1 mole of CO2.
Now, convert the given mass of O2 to moles using its molar mass:
- 3.4 grams O2 x (1 mol O2 / 32 grams O2) = 0.10625 mol O2.
Finally, use the mole ratio to determine the moles of CO2 produced:
- 0.10625 mol O2 x (1 mol CO2 / 2 mol O2) = 0.053125 mol CO2.
Convert the moles of CO2 to grams using its molar mass:
- 0.053125 mol CO2 x (44 grams CO2 / 1 mol CO2) = 2.325 grams CO2.
Therefore, the mass of CO2 produced when 3.4 grams of O2 reacts is approximately 2.3 grams. The correct answer is c. 2.3g.