Can someone try this out so I can see if I'm correct?
An 870 g river water sample contains 2 mg of cadmium. Express the concentration in parts per million.
I got 2.30 ppm.
Looks good to me.
Thanks.
To express the concentration of cadmium in parts per million (ppm), we need to calculate the ratio of the mass of cadmium to the mass of the river water sample and then multiply it by one million.
Step 1: Convert the mass of cadmium to kilograms.
2 mg = 2 * 10^(-3) g = 2 * 10^(-6) kg
Step 2: Convert the mass of the river water sample to kilograms.
870 g = 870 * 10^(-3) kg = 0.87 kg
Step 3: Calculate the concentration of cadmium in ppm.
Concentration (ppm) = (mass of cadmium / mass of river water sample) * 10^6
Concentration (ppm) = (2 * 10^(-6) kg / 0.87 kg) * 10^6
Concentration (ppm) = 2.3 ppm
Therefore, the concentration of cadmium in the river water sample is 2.3 ppm. Your answer is correct!
To find the concentration in parts per million (ppm), you can follow these steps:
1. Determine the mass of the substance of interest (cadmium in this case) in grams. In the given problem, it is stated that there are 2 mg (milligrams) of cadmium present.
2. Convert the mass of the substance to grams. Since 1 mg is equal to 0.001 grams, you can multiply the mass in milligrams by 0.001 to convert it to grams. In this case, 2 mg * 0.001 g/mg = 0.002 g.
3. Calculate the concentration in ppm. Concentration in ppm is defined as the number of parts of solute (cadmium) per million parts of solution (water). Since the total mass of the solution is given as 870 g, you can divide the mass of the solute (0.002 g) by the total mass of the solution (870 g) and multiply by 1,000,000 to get the concentration in ppm.
Concentration (ppm) = (mass of solute / mass of solution) * 1,000,000
Concentration (ppm) = (0.002 g / 870 g) * 1,000,000
Concentration (ppm) = 2.2988 ppm
Therefore, the concentration of cadmium in this river water sample is approximately 2.30 ppm, not 2.30 ppm as you mentioned.