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The amount ofcalcium present in milk can be determined by adding oxalate to asample and measuring the massof calcium oxalate pre

Sauron [17]

<u>Answer:</u> The mass percent of calcium in milk is 0.107 %

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of calcium oxalate = 0.429 g

Molar mass of calcium oxalate = 128.1 g/mol

Putting values in equation 1, we get:

$\text{Moles of calcium oxalate}=\frac{0.429g}{128.1g/mol}=0.0033mol$

The given chemical equation follows:

$Na_2C_2O_4(aq.)+Ca^{2+}(aq.)\rightarrow CaC_2O_4(s)+2Na^+(aq.)$

Sodium oxalate is present in excess. So, it is considered as an excess reagent. And, calcium ion is a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of calcium oxalate is produced from 1 mole of calcium ion

So, 0.0033 moles of calcium oxalate is produced from = $\frac{1}{1}\times 0.0033=0.0033mol$ of calcium ions

Now, calculating the mass of calcium ions by using equation 1, we get:

Moles of calcium ions = 0.0033 moles

Molar mass of calcium ions = 40 g/mol

Putting values in equation 1, we get:

$0.0033mol=\frac{\text{Mass of calcium ions}}{40g/mol}\\\\\text{Mass of calcium ions}=(0.0033mol\times 40g/mol)=0.132g$

To calculate the mass percentage of calcium ions in milk, we use the equation:

$\text{Mass percent of calcium ions}=\frac{\text{Mass of calcium ions}}{\text{Mass of milk}}\times 100$

Mass of milk = 125 g

Mass of calcium ions = 0.132 g

Putting values in above equation, we get:

$\text{Mass percent of calcium ions}=\frac{0.132g}{125g}\times 100=0.107\%$

Hence, the mass percent of calcium in milk is 0.107 %

7 0

2 years ago

Investigate and explain that when a force is applied to an object but it does not move, it is because another opposing force is

N76 [4]

Answer:

4. Force 1 Force 2 Comparison of Forces

Friction Gravity Force 1 is equal to Force 2

Explanation:

5 0

3 years ago

Read 2 more answers

An amide may be produced by reacting an acid chloride with

Elanso [62]

Answer:

An amide may be produced by reacting an acid chloride with ammonia.

8 0

3 years ago

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Pls help asap!!!!

AVprozaik [17]

Answer: The pressure of the He is 2.97 atm

Explanation:

According to Dalton's law, the total pressure is the sum of individual pressures.

$p_{total}=p_{N_2}+p_{O_2}+p_{He}.$

Given : $p_{total}$ =total pressure of gases = 6.50 atm

$p_{N_2}$ = partial pressure of Nitrogen = 1.23 atm

$p_{O_2}$ = partial pressure of oxygen = 2.3 atm

$p_{He}$ = partial pressure of Helium = ?

putting in the values we get:

$6.50atm=1.23atm+2.3atm+p_{He}$

$p_{He}=2.97atm$

The pressure of the He is 2.97 atm

3 0

3 years ago

During an ionic bond, electrons are basically transferred from one atom to another whereas in a covalent bond, electron pairs ar

Ad libitum [116K]

The answer is true......

8 0

3 years ago