Calculate the amount of water (in grams) that must be added to 5.00 g urea in preparation of 16.2% by mass solution.
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To calculate the amount of water that needs to be added, we need to determine the mass of urea in the desired final solution.
Step 1: Calculate the mass of urea needed in the desired solution:
Mass of urea = Percent by mass × Total mass of solution
Mass of urea = 16.2% × Total mass of solution
Step 2: Set up an equation using the mass of urea:
Mass of urea = Mass of urea in 5.00 g urea + Mass of water added
Step 3: Rearrange the equation to solve for the mass of water added:
Mass of water added = Total mass of solution - Mass of urea in 5.00 g urea
Now, let's calculate the mass of urea and water.
Step 1: Calculate the mass of urea needed in the desired solution:
Mass of urea = 16.2% × Total mass of solution
Since the mass of urea in 5.00 g urea is already known, we can assume the total mass of the solution is 5.00 g + mass of water added.
Step 2: Set up an equation using the mass of urea:
Mass of urea = Mass of urea in 5.00 g urea + Mass of water added
16.2% × (5.00 g + mass of water added) = Mass of urea in 5.00 g urea
To solve this equation, we need to determine the mass of urea in 5.00 g urea.
Given:
Mass of urea = 5.00 g
Now, let's calculate the mass of urea:
Mass of urea = 5.00 g
Since the desired concentration of urea in the solution is 16.2% by mass, we can calculate the mass of urea in 5.00 g urea:
Mass of urea in 5.00 g urea = 16.2% × 5.00 g
Step 3: Rearrange the equation to solve for the mass of water added:
Mass of water added = Total mass of solution - Mass of urea in 5.00 g urea
Now, let's substitute the values and calculate the mass of water added:
Mass of water added = (5.00 g + mass of water added) - (16.2% × 5.00 g)
Simplifying the equation:
Mass of water added = 5.00 g - (0.162 × 5.00 g)
Mass of water added = 5.00 g - 0.81 g
Mass of water added = 4.19 g
Therefore, approximately 4.19 grams of water should be added to 5.00 grams of urea to prepare a 16.2% by mass solution.
To calculate the amount of water needed to prepare a 16.2% urea solution, we first need to determine the mass of urea in the solution and then calculate the mass of water required.
Given:
Mass of urea (m₁) = 5.00 grams
Percentage by mass (w/w) = 16.2%
Step 1: Calculate the mass of urea in the solution (m₂).
The mass of urea in the solution can be calculated by multiplying the mass of the solution (m) by the percentage by mass (w/w) (expressed as a decimal):
m₂ = m × (w/w)
= m × (16.2/100)
Step 2: Calculate the mass of the solution (m).
To calculate the mass of the solution, we need to consider that the solution is composed of both urea and water. Therefore:
m = m₁ + m₂
m = mass of urea + mass of water
Step 3: Solve for the mass of water (m_water).
Rearranging Step 2, we have:
m_water = m - m₁
Now, let's calculate step by step:
Step 1: Calculate the mass of urea in the solution (m₂).
m₂ = 5.00 g × (16.2/100)
= 0.81 g
Step 2: Calculate the mass of the solution (m).
The mass of the solution will be the sum of the mass of urea (m₁) and the mass of water (m_water).
m = 5.00 g + 0.81 g
= 5.81 g
Step 3: Solve for the mass of water (m_water).
m_water = m - m₁
= 5.81 g - 5.00 g
= 0.81 g
Therefore, 0.81 grams of water must be added to 5.00 grams of urea to prepare a 16.2% by mass solution.
% w/w = (g solute/gm soln)*100 =
?
(5g/x)*100 = 16.2
x = (500/16.2) = approx 30.9 g solution.
g urea + g H2O = 30.9 total.
Calculate g H2O to add.