Need help calculating percent composition

In summary, the speaker needed help calculating the percent composition of casien and lactose in milk. They used 50ml of nonfat milk and obtained 1.599g of casien and 1.610g of lactose. They were unsure of how to convert these values into ml using density and asked for guidance. However, they were able to figure out the solution when a classmate provided a different version of the procedure that included the density of milk.
  • #1
babbagee
74
0
Hello,

I need some help calculating the pecent composition of casien and lactose in milk. I started out with 50ml of nonfat milk, at the end of the experiment I got 1.599g casien and 1.610g of lactose. My idea was to convert these values into ml using density but I could not find the densities. Can someone lead me in the right direction.
 
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  • #2
Rajvirnijjar said:
Hello,

I need some help calculating the pecent composition of casien and lactose in milk. I started out with 50ml of nonfat milk, at the end of the experiment I got 1.599g casien and 1.610g of lactose. My idea was to convert these values into ml using density but I could not find the densities. Can someone lead me in the right direction.

if you are doing % composition by weight, then what is the weight of 50ml of milk? that would be all that you would need.
 
  • #3
Thats the problem, I just used 50ml of milk, i did not weigh it. The procedure I was following just said to use 50ml of milk, it did not say anything about weighing it.
 
  • #4
You may give your results as % w/v - stupid and rather faulty units, but better then nothing.
 
  • #5
I actually figure it out. The procedure I was using did not give the density of milk, but one of my classmates had a different version of the procedure which gave the density. That was the only reason i was having this problem. I did not know the density. Thanks for your guys help
 

What is percent composition and why is it important?

Percent composition is the percentage of each element present in a compound by mass. It is important because it provides information about the relative amounts of each element in a compound and can be used to determine the chemical formula of a compound.

How do you calculate percent composition?

The percent composition of an element is calculated by dividing the mass of the element by the total mass of the compound and multiplying by 100%. This can be expressed as: (mass of element / mass of compound) x 100%.

What is the significance of percent composition in chemistry?

Percent composition is significant in chemistry because it can help identify unknown compounds, determine the amount of each element in a compound, and can be used to predict the properties of a compound.

What are some common mistakes when calculating percent composition?

One common mistake is not converting all units to the same measurement (e.g. grams) before calculating. Another mistake is rounding too early in the calculation, leading to inaccurate results. It is also important to make sure all elements in the compound are included in the calculation.

How can percent composition be used in real-world applications?

Percent composition is used in various industries such as pharmaceuticals, food and beverage, and environmental analysis. It is used to determine the purity of a substance, to ensure the correct amount of ingredients in a product, and to monitor air and water quality.

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