Multiple Choice
If you have 5 mL of a solution with a molarity of 1.2×10⁻⁵ M and add 0.976 g of bleach with a density of 1.08 g/mL, what is the initial concentration of the hypochlorite ion (OCl⁻) in the reaction?
6. Chemical Quantities & Aqueous Reactions
Molarity
Multiple Choice
How many grams of CaCl_2 are present in 250 mL of a 2.0 M CaCl_2 solution?
A
13.8 g
B
55.5 g
C
11.1 g
D
27.5 g
Verified step by step guidance1
Identify the given information: volume of solution = 250 mL, molarity (M) of CaCl_2 = 2.0 M. Remember to convert volume from milliliters to liters because molarity is in moles per liter.
Convert the volume from milliliters to liters using the conversion factor: \(1\, \text{L} = 1000\, \text{mL}\). So, \(250\, \text{mL} = \frac{250}{1000} = 0.250\, \text{L}\).
Calculate the number of moles of CaCl_2 in the solution using the molarity formula: \(\text{moles} = M \times \text{volume in liters}\). Substitute the values to find moles of CaCl_2.
Find the molar mass of CaCl_2 by adding the atomic masses of calcium (Ca) and chlorine (Cl). Calcium has an atomic mass of approximately 40.08 g/mol, and chlorine has an atomic mass of approximately 35.45 g/mol. Since there are two chlorine atoms, multiply chlorine's atomic mass by 2 and add to calcium's atomic mass.
Calculate the mass of CaCl_2 by multiplying the number of moles by the molar mass: \(\text{mass} = \text{moles} \times \text{molar mass}\). This will give the mass of CaCl_2 in grams present in 250 mL of the solution.
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