If the density of ocean water at a depth of 1.00 x 104 m is 1.071 g/mL and if 20.0 g of water at that depth contains 197mg of potassium chloride, what is the molarity of potassium chloride in the sample? It wants it in M.
Oh, buoy! Let's dive right in! To find the molarity of potassium chloride (KCl) in the sample, we need to know the number of moles of KCl present.
First, let's convert the mass of KCl from milligrams to grams. 197 mg of KCl is equal to 0.197 g.
Next, we divide the mass of KCl by the molar mass of KCl to find the number of moles. The molar mass of KCl is 74.55 g/mol.
Moles of KCl = (0.197 g) / (74.55 g/mol) = 0.00264 mol
Now, we need to find the volume of water in liters. Since the density of ocean water is given as 1.071 g/mL, we can use that information to find the volume.
Volume of water = Mass of water / Density of water
Volume of water = 20.0 g / 1.071 g/mL = 18.65 mL
We need to convert the volume from milliliters to liters by dividing by 1000.
Volume of water = 18.65 mL / 1000 = 0.01865 L
Finally, we calculate the molarity of KCl by dividing the number of moles by the volume in liters.
Molarity = Moles of solute / Volume of solution
Molarity = 0.00264 mol / 0.01865 L = 0.1414 M
Tada! The molarity of potassium chloride in the sample is approximately 0.1414 M.
To find the molarity of potassium chloride in the sample, we need to calculate the number of moles of potassium chloride and then divide it by the volume of the solution in liters. Here are the step-by-step calculations:
Step 1: Calculate the number of moles of potassium chloride.
Given:
Mass of water = 20.0 g
Mass of potassium chloride = 197 mg = 0.197 g
The mass of potassium chloride is the difference between the total mass of the water sample and the mass of water:
Mass of potassium chloride = Mass of water sample - Mass of water
Mass of potassium chloride = 20.0 g - 0.197 g
Mass of potassium chloride = 19.803 g
Now we can calculate the number of moles of potassium chloride using its molar mass:
Molar mass of potassium chloride (KCl) = 39.10 g/mol (for potassium) + 35.45 g/mol (for chlorine)
Molar mass of potassium chloride = 74.55 g/mol
Number of moles of potassium chloride = Mass of potassium chloride / Molar mass of potassium chloride
Number of moles of potassium chloride = 19.803 g / 74.55 g/mol
Number of moles of potassium chloride ≈ 0.2655 mol
Step 2: Calculate the volume of the solution in liters.
Given:
Density of ocean water at a depth of 1.00 x 10^4 m = 1.071 g/mL
Density is defined as mass divided by volume:
Density = Mass / Volume
Rearranging the equation, we can solve for volume:
Volume = Mass / Density
Volume of solution = Mass of water / Density of water
Volume of solution = 20.0 g / 1.071 g/mL
Volume of solution ≈ 18.6834 mL
To convert mL to L, divide by 1000:
Volume of solution ≈ 18.6834 mL / 1000
Volume of solution ≈ 0.0186834 L
Step 3: Calculate the molarity of potassium chloride.
Molarity = Number of moles / Volume of solution
Molarity = 0.2655 mol / 0.0186834 L
Molarity ≈ 14.212 M
Therefore, the molarity of potassium chloride in the sample is approximately 14.212 M.
To determine the molarity of potassium chloride in the sample, we need to follow these steps:
1. Calculate the volume of the water sample:
Since the density of ocean water at a depth of 1.00 x 104 m is given as 1.071 g/mL, we can use this information to find the volume of water in the sample.
Given: mass of water = 20.0 g
Density of water = 1.071 g/mL
Volume of water = mass of water / density of water
Volume of water = 20.0 g / 1.071 g/mL
2. Convert the mass of potassium chloride to moles:
Given: mass of potassium chloride = 197 mg
First, we need to convert the mass from mg to g:
mass of potassium chloride = 197 mg × (1 g / 1000 mg)
Next, we need to convert the mass to moles using the molar mass of potassium chloride. The molar mass of potassium chloride (KCl) is 74.55 g/mol (39.10 g/mol for potassium + 35.45 g/mol for chloride):
moles of potassium chloride = mass of potassium chloride / molar mass of KCl
moles of potassium chloride = (197 g / 1000) g / 74.55 g/mol
3. Calculate the molarity of potassium chloride:
Now that we have the moles of potassium chloride and the volume of the water sample, we can calculate the molarity.
Molarity (M) = moles of solute / volume of solvent (in liters)
Given that the solution is water, we can use the volume of water calculated in step 1.
Remember to convert the volume from mL to L:
Molarity of potassium chloride = moles of potassium chloride / volume of water (in liters)
By following these steps and applying the given values, you can calculate the molarity of potassium chloride in the sample.
what is the volume of 20 g of water?
20 g /1.071 g/mL = 18.674 mL
so
197 *10^-3 g KCl /18.674*10^-3 L
= 10.55 grams/liter
Mol mass of KCl = 74.5 grams/mol
(10.55 grams/Liter)/74.5 grams/mol
= .142 mols/Liter