pleast help me work this prob
lead is a toxic meatal that affects the central nervous system. a Pb-contaminated water sample contains 0.0011% Pb by mass. What vilume of the water in milliliters contains 115g of Pb? (assume that the density of the solution is 1.0g/ml
0.0011% by mass means that for every 100 grams of solution (water), there is 0.0011 grams of lead.
By proportions noting 1 ml of water weighs 1 g:
100 ml : 0.0011 g
x ml : 115 g
So by cross multiplication:
x = 100*115/0.0011=10454545 ml
= 10454.545 l
I obtained the same number; I would express it as 1.0E4L to two significant figures.
Thanks Dr. Bob, I forgot about that!
Calculate the mass of a sample of gold that
occupies 0.498 cm3
. The density of gold is
19.3 g/cm3
.
Answer in units of g.
To find the volume of water containing 115g of Pb, we first need to determine the mass of the water contaminated with lead.
Given:
% of Pb in the water sample = 0.0011%
Mass of Pb = 115g
Density of the solution = 1.0g/mL
Step 1: Determine the mass of the water contaminated with lead
To find this, we need to convert the given percentage to a decimal fraction.
0.0011% = 0.0011/100 = 0.000011 (decimal fraction)
Now, we can set up the equation to determine the mass of the water:
Mass of water = (Mass of Pb) / (Decimal fraction of Pb)
Mass of water = 115g / 0.000011 = 10,454,545.45g (rounded to 2 decimal places)
Step 2: Determine the volume of the water
Since the density of the solution is given as 1.0g/mL, we can directly convert the mass of water to volume.
Volume of water = Mass of water / Density of the solution
Volume of water = 10,454,545.45g / 1.0g/mL = 10,454,545.45 mL (rounded to 2 decimal places)
Therefore, the volume of water that contains 115g of Pb is approximately 10,454,545.45 mL.