Reaction Stoich
Hydrobromic acid (HBr) dissolves solid iron according to the reaction:
Fe(s)+ 2HBr(aq) -> FeBr₂(aq)+H₂(g)
What mass of HBr do you need to dissolve a 3.2 g pure bar?
Given:m Fe = 3.2 g, Molar ratios through the balanced equation
Strategy:g Fe -> moles Fe -> moles HBr -> g HBr
How many milliliters of a 12.0 M NaOH solution must you dilute with water in order to make 300.0 ml of a 1.0 M NaOH solution?
Given:
M1 = 12.0 M, V2 = 300 mL, M2 = 1.0 M
Strategy:M1V1 = M2V2
How much heat is required to warm 1.5 L of water from 25.0 °C to 100.0 °C? (The density of water is 1.0 g/mL, and its specific heat is 4.18 J/g°C)
Given: d = 1.0 g/mL, Cs = 4.18 J/g°C, Ti = 25 °C, Tf = 100.0 °C
Strategy: q = mCs∆T, d water -> g water
How much heat is emitted if 3.0 g of CH3OH are burned in excess oxygen gas?
2CH3OH(g)+3O2(g)-> 2CO2(g)+4H2O(g)
∆H = -1277 kJ
Given: ∆H = -1277 kJ, molar ratios, m CH3OH = 3.0 g
Strategy: g CH3OH -> moles CH3OH -> kJ
What is the volume of a balloon that contains 0.118 moles of helium gas, at a pressure of 0.97 atm and a temperature of 305 K?
Given: n = 0.118 moles, P = 0.97 atm, T = 305 K
Strategy: PV = nRT, solve for V
Aspirin (C9H8O4)can be made in the lab as shown by the chemical reaction:
C4H6O3+C7H6O3->C9H8O4+C2H4O2
A student synthesizes aspirin using 3.0 mL of C4H6O3 (density = 1.08 g/mL) and 1.25 g of C7H6O3. What is the theoretical yield of aspirin in moles?
Given:
V C4H6O3: 3 mL, d C4H6O3: 1.08 g/mL, m C7H6O3: 1.25 g
Strategy:
mL C4H6O3 -> g C4H6O3 -> moles C4H6O3 -> moles C9H8O4
g C7H6O3 -> moles C7H6O3 -> moles C9H8O4
Water is added to a 3.60 M KCl stock solution to a final diluted concentration of 0.450 M KCl. If 1.0 L of KCl stock solution is used to make the new solution, what volume of water must be added to achieve the 0.450 M KCl concentration?
Given: M1 = 3.6 M, M2 = 0.450 M, V1 = 1.0 L
Strategy:M1V1 = M2V2, V2 = 1.0 L KCL + ___ L H2O
A piece of gold with a mass of 31.1 g and an initial temperature of 69.3 °C is dropped into 64.2 g of water at 27.8 °C. What is the final temperature of both substances at thermal equilibrium?
Given: mAu = 31.1 g, TiAu = 69.3 °C, mH2O = 64.2 g, TiH2O = 27.8 °C
Strategy: q = mCs∆T, set q's equal and opposite
What magnitude energy will be released (in Joules) when 15.0 moles of nitrogen monoxide gas are mixed with 6.0 moles of oxygen?
2NO(g)+O2(g)->2NO2(g) ∆H = -113.1 kJ
Given: nNO = 15 moles, nO2 = 6.0 moles, ∆H = -113.1 kJ, molar ratios
Strategy:
moles NO -> kJ -> J
moles O2 -> kJ -> J
Choose the smaller number
A 48.3 mL sample of a gas in a cylinder is warmed from 295.2 K to 360.2 K. What is its volume at the final temperature?
Given: V1 = 48.3 mL, T1 = 295.2 K, T2 = 360.2 K
Strategy: V1/T1 = V2/T2