Answer:
1.67 M
Explanation:
75.0 g *1 mol/180 g = (75/180) mol of glucose
250 mL = 0.250 L
(75/180)/0.250 = 1.67 mol/L =1.67 M
Answer:
2.174 gm
Explanation:
PV = nRT n = number of moles
R = gas constant = .082057 L-atm/(K-mol)
T must be in units of K
.870 (3.95) = n (.082057)(35+273.15)
solve for n = .1359 moles
Methane mole weight (CH4) = 16 gm / mole
.1359 moles * 16 gm/mole = 2.174 gm
Answer:
52.07 L H₂
Explanation:
Before you can find the volume of H₂, you need to find the moles of H₂. To do this, you need to (1) convert grams Mg to moles (via the atomic mass) and then (2) convert moles Mg to moles H₂ (via the mole-to-mole ratio from equation coefficients).
Atomic Mass (Mg): 24.30 g/mol
1 Mg(s) + 2 HCl(aq) ---> MgCl₂(aq) + 1 H₂(g)
^ ^
56.49 g Mg 1 mole 1 mole H₂
------------------- x ----------------- x -------------------- = 2.32 moles H₂
24.30 g 1 mole Mg
Now that you know the moles of H₂, you need to determine the volume at STP. To do this, you need to set up a proportion comparing the mole value versus the volume. Then, you can cross-multiply to solve for the unknown volume. The final answer should have 4 sig figs to match the given values.
1 mole 2.32 moles
-------------- = -------------------- <----- Set up proportion
22.4 L ? L
(1 mole) x ? L = 52.07 <----- Cross-multiply
? L = 52.07 <----- Divide both sides by 1 mole
