# What is the percentage by mass of ammonium phosphate in the fertilizer?

• littlebearrrr
I would just specify that the 3.741 g of barium phosphate is the product of the reaction and not the starting amount. Otherwise, great job!In summary, the conversation discusses the process of determining the percentage by mass of ammonium phosphate in a fertilizer through a chemical reaction. The fertilizer, which contains ammonium phosphate and other substances, is mixed with barium chloride and the resulting product is found to contain 3.741 g of barium phosphate. Using this information, the percentage of ammonium phosphate in the fertilizer is calculated to be 25.65%.
littlebearrrr

## Homework Statement

Many fertilizers contain ammonium phosphate as a source of phosphorus and nitrogen. A 7.225 g sample of a fertilizer is dissolved in water and mixed with excess barium chloride solution, and the following reaction occurs:

2(NH4)3PO4(aq) + 3BaCl2(aq) -> Ba3(PO4)2(s) + 6NH4Cl(aq)

The product mixture is found to contain 3.741 g of barium phosphate. Using this info, calculate the percentage by mass of ammonium phosphate in the fertilizer.

## Homework Equations

% by mass = grams of fertilizer/molar mass of fertilizer x 100
(unsure if that's correct, but that's what I think it should be)

## The Attempt at a Solution

I started by taking the given amount of barium phosphate to find moles of ammonium phosphate. I think I need to use that to find grams of ammonium phosphate. However, I am also having difficulty trying to understand what the problem is specifying as the fertilizer. Is it the ammonium phosphate AND the barium chloride, or just the ammonium phosphate?

littlebearrrr said:

## Homework Equations

% by mass = grams of fertilizer/molar mass of fertilizer x 100
(unsure if that's correct, but that's what I think it should be)
There is no such thing as the molar mass of a fertilizer, as it is a mixture. You want to know what percentage of the total mass is due to ammonium phosphate:

% by mass = mass of ammonium phosphate / total mass of fertilizer

littlebearrrr said:

## The Attempt at a Solution

I started by taking the given amount of barium phosphate to find moles of ammonium phosphate.
You can do that. You can also calculate everything using just masses.

littlebearrrr said:
I think I need to use that to find grams of ammonium phosphate. However, I am also having difficulty trying to understand what the problem is specifying as the fertilizer. Is it the ammonium phosphate AND the barium chloride, or just the ammonium phosphate?
The fertilizer is a mixture of ammonium phosphate and other stuff. The barium chloride is added in the lab.

Thank you DrClaude! Makes a whole lot of sense now (Answer I got: 25.65%)

Steps:
Grams of barium phosphate -> moles of barium phosphate -> moles of ammonium phosphate -> grams of ammonium phosphate.

Then divided grams of ammonium phosphate by grams of fertilizer (multiplied by 100).

Last edited:
littlebearrrr said:

Looks good.

1 person

Based on the information given, it seems that the fertilizer in this problem is just the ammonium phosphate. This is because the reaction provided only involves the ammonium phosphate and barium chloride, and the goal is to find the percentage by mass of ammonium phosphate in the fertilizer.

To solve this problem, you can first use the given information to find the moles of barium phosphate produced in the reaction. From there, you can use the mole ratio between barium phosphate and ammonium phosphate (2:1) to find the moles of ammonium phosphate present in the original sample.

Next, you can use the molar mass of ammonium phosphate to convert the moles to grams. Finally, you can use the formula % by mass = grams of ammonium phosphate/molar mass of fertilizer x 100 to find the percentage by mass of ammonium phosphate in the fertilizer.

I hope this helps! Let me know if you have any further questions or need clarification.

## 1. What is percentage by mass?

Percentage by mass is a way to express the relative amount of a particular element or compound in a substance. It is calculated by dividing the mass of the element or compound by the total mass of the substance and multiplying by 100.

## 2. How do you calculate percentage by mass?

To calculate percentage by mass, you need to know the mass of the element or compound you are interested in, as well as the total mass of the substance. Divide the mass of the element or compound by the total mass, then multiply by 100 to get the percentage.

## 3. What is the purpose of calculating percentage by mass?

Calculating percentage by mass is useful for determining the composition of a substance and understanding the relative amounts of different elements or compounds present. It can also be used to compare the composition of different substances.

## 4. Can percentage by mass be greater than 100%?

No, percentage by mass cannot be greater than 100%. This would indicate that the substance contains more of the element or compound being measured than the total mass of the substance, which is not possible.

## 5. How is percentage by mass different from percentage by volume?

Percentage by mass and percentage by volume are similar concepts, but they measure different properties. Percentage by mass is a measure of the relative amount of an element or compound in a substance, while percentage by volume is a measure of the relative amount of space occupied by a substance. They can give different results for the same substance, depending on its density.

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