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4 years ago

Why do soluble salts have to be made by titration, using an indicator?

1 answer:

7 0

This technique can be used to make pure crystals of a soluble salt.
The burette is filled with hydrochloric acid.
A known quantity of alkali (say 50 cm3 sodium hydroxide)
is released from a pipette into the conical flask.
The tap on the burette is turned open to allow
the acid to be added drop by drop into the alkali.
The alkali contains an indicator (phenolphthalein)
which is pink in an alkali and colorless in an acid.

When enough acid has been added to neutralize
the alkali, the indicator changes from
pink to colorless. This is the end point of the titration.

The titration can be repeated using the same amounts
of acid and alkali but without the indicator.
Pure salt crystals which are free from indicator
can then be crystallized from the neutral solution.

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A sample of oxygen gas was collected via water displacement. since the oxygen was collected via water displacement, the sample i

mylen [45]

The sample of oxygen gas was collected through water displacement. So, the gas collected will be a mixture of oxygen and water vapor.

Given that the total pressure of the mixture of gases containing oxygen and water vapor = 749 Torr

Vapor pressure of pure water at $26.4^{0}C$ =25.81mmHg

= $25.81 mmHg*\frac{1 Torr}{1 mmHg} =25.81 Torr$

According to Dalton's law of partial pressures,

Total pressure = Partial pressure of Oxygen gas + Partial pressure of water

749 Torr = Partial pressure of Oxygen gas + 25.81 Torr

Partial pressure of Oxygen gas = 749 Torr - 25.81 Torr = 723.19 Torr

Therefore the partial pressure of Oxygen gas in the mixture collected will be 723.19 Torr

6 0

3 years ago

What is vaccine (question answer)

Ket [755]

Above answer is correct

6 0

3 years ago

A compound is 40% carbon, 6.7% hydrogen, and 53.3% oxygen. What is the empirical formula?

Ahat [919]

Answer:

O H C

Moles in 100g 3.33 6.65 3.33

Ratio 1.00 2.00 1.00

Possible empirical formula = $OH_{2}C$

6 0

4 years ago

Read 2 more answers

3.65 gram of hcl is dissolved in 180 gram of water. Find the total number of molecules of hydrogen

Morgarella [4.7K]

Answer:

$Molec_{\ H_{tot}}=1.206x10^{25}molec$

Explanation:

Hello.

In this case, taking into account that HCl has one molecule of hydrogen per mole of compound which weights 36.45 g/mol, we compute the number of molecules of hydrogen in hydrochloric acid by considering the given mass and the Avogadro's number:

$molec_{\ H}=3.65gHCl*\frac{1molHCl}{36.45gHCl} *\frac{1molH}{1molHCl}*\frac{6.022x10^{23}molec_\ H}{1molH} =6.03x10^{22}molec$

Now, from the 180 g of water, we see two hydrogen molecules per molecule of water, thus, by also using the Avogadro's number we compute the molecules of hydrogen in water:

$molec_{\ H}=180gH_2O*\frac{1molH_2O}{18gH_2O} *\frac{2molH}{1molH_2O}*\frac{6.022x10^{23}molec_\ H}{1molH} =1.20x10^{25}molec$

Thus, the total number of molecules turns out:

$Molec_{\ H_{tot}}=6.03x10^{22}+1.20x10^{25}\\\\Molec_{\ H_{tot}}=1.206x10^{25}molec$

Regards.

6 0

4 years ago

Please help, I really don’t understand this!!!

kap26 [50]

Analysing the Question:

We are given the balanced equation:

C₆H₁₂O₆ + 6O₂→ 6CO₂ + 6H₂O

from this equation, we can say that: for every 1 mole of Glucose, we need 6 moles of Oxygen

Moles of Glucose used in the reaction:

Molar mass of Glucose = 180 grams / mol

Given mass of Glucose = 1 gram

Mole of Glucose = Given mass / Molar mass

Moles of Glucose = 1 / 180 moles

Mass of Oxygen required:

We know that for every mole of Glucose, we need 6 moles of Oxygen

So, for 1/180 moles of Glucose, we need 6 / 180 = 1 / 30 moles of Oxygen

Mass of 1 / 30 moles of Oxygen:

Mass = Molar mass * number of moles

Mass of Oxygen = 32 * 1/30

Mass of Oxygen = 32 / 30

Mass of Oxygen = 1.06 grams

5 0

3 years ago