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kow [346]
2 years ago
6

What sample size (grams) of Na3PO4 (FW 164.00) known to be 50.00% pure should be used to consume exactly 40.00 mL of 0.1000 M HC

l to reach the 2nd end point
Chemistry
1 answer:
Mkey [24]2 years ago
3 0

Answer:

0.109 g.

Explanation:

Equation of the reaction:

Na3PO4 + 3HCl --> 3NaCl + H3PO4

Number of moles of HCl = molar concentration × volume

= 0.1 × 0.04

= 0.004 mol.

By stoichiometry, 1 mole of Na3PO4 neutralises 3 moles of HCl. Therefore, number of moles of Na3PO4 = 0.004/3

= 0.0013 mol

Mass of Na3PO4 = molar mass × number of moles

= 0.0013 × 164

= 0.219 g

Since 50% of Na3PO4 was present in the sample. Let 100 g be the total mass of the substance

= 0.219 × 50 g/100 g

= 0.109 g.

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Calculate the freezing point of a 0.100 m aqueous solution of k2so4, taking interionic attractions into consideration by using t
Leokris [45]
Ionic  salt  dissociate  completely  in  water   particularly in  water at  low  concentration.
 The  molal  freezing point  of  depression constant  for  water is 1.85kg/k/mol
therefore depression  of  freezing  point =1.853  x 0.100  x  2.32=0.429  degrees  celsius
hence  solute  freeze at - 0.429  degree  celsius
3 0
2 years ago
what is the new pressure acting on a 2.5 l balloon if its original volume was 5.8 l at 3.7 ATM of pressure
Ivan

Answer : The new pressure acting on a 2.5 L balloon is, 8.6 atm.

Explanation :

Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

P\propto \frac{1}{V}

or,

P_1V_1=P_2V_2

where,

P_1 = initial pressure = 3.7 atm

P_2 = final pressure = ?

V_1 = initial volume = 5.8 L

V_2 = final volume = 2.5 L

Now put all the given values in the above equation, we get:

3.7atm\times 5.8L=P_2\times 2.5L

P_2=8.6atm

Thus, the new pressure acting on a 2.5 L balloon is, 8.6 atm.

8 0
2 years ago
in collecting the precipitate, why would it be inappropriate to heat the reacted mixture and evaporate off the water?
djverab [1.8K]
In collecting the precipitate, it is inappropriate to heat <span>the reacted mixture and evaporate off the water because it is possible that the mixture contains other substances that precipitates as well when the mixture is being heated so you will not be able to collect what you want.</span>
6 0
2 years ago
What is the value of Keq for the reaction expressed in scientific notation? 2.1 x 10-2 2.1 x 102 1.2 x 103 1.2 x 10-3
Lady_Fox [76]

Complete question:

Consider the reaction.

At equilibrium at 600 K, the concentrations are as follows.

2HF -----> H₂ + F₂

[HF] = 5.82 x 10-2 M

[H2] = 8.4 x 10-3 M

[F2] = 8.4 x 10-3 M

What is the value of Keq for the reaction expressed in scientific notation?

2.1 x 10-2

2.1 x 102

1.2 x 103

1.2 x 10-3

Answer:

2.1 × 10^-2

Explanation:

Kequilibrum(Keq) = product/reactant

Equation for the reaction :

2HF -----> H₂ + F₂

Therefore,

Keq = [H2][F2] / [HF]^2

Keq = [8.4 x 10-3][8.4 x 10-3] / [5.82 x 10-2]^2

Keq = [70.56 × 10^(-3 + - 3)]/[33.8724 × 10^(-2×2)]

Keq = [70.56 × 10^-6] / [33.8724 × 10^-4]

Keq = 2.0665 × 10^(-6 - (-4))

Keq = 2.0665 × 10^(-6 + 4)

Keq = 2.1 × 10^-2

7 0
2 years ago
Read 2 more answers
In the following list, only ________ is not an example of a chemical reaction. the production of hydrogen gas from water the tar
Vika [28.1K]

Answer: Option (c) is the correct answer.

Explanation:

A chemical reaction is defined as the reaction where a chemical bond will break in order to form a new bond due to the formation of a new substance.

For example, 2Na + Cl_{2} \rightarrow 2NaCl

Here, NaCl is the new substance that is formed. A chemical reaction will always bring change in chemical composition of a substance.

The production of hydrogen gas from water, the tarnishing of a copper penny, charging a cellular phone and burning a plastic water bottle are all chemical reactions.

Whereas a reaction where no change in chemical composition of a substance takes place is known as a physical reaction.

For example, chopping a log into sawdust will change the shape but it will not bring any change in chemical composition of the substance.

Thus, we can conclude that in the following list, only chopping a log into sawdust is not an example of a chemical reaction.

8 0
2 years ago
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