4Na+ O2 --> 2Na20 If 4 moles of Na react completely, how many moles of Na2O form?

Q2. 0.254 g of KHP (204 g/mol) titrated against 20.0 mL of unknown NaOH (40.0 g/mol) solution to get the end point of phenolpht

Vera_Pavlovna [14]

Answer:

Mass concentration (g/L) = 2.49g/L.

Explanation:

No. of moles = $\frac{mass}{molar mass}$

= $\frac{0.254}{204}$ = 0.001245 moles

Concentration of KHP (C1) in litres = n/v

= $\frac{0.001245}{0.02}$ = 0.062 mol/L

We know that:

$C_{1} V_{1}$ = $C_{2} V_{2}$

where c1v1 and c2v2 are the products of concentration and volumes of KHP and NaOH respectively.

Since mole ratio is 1 : 1.

1 mole of NaOH - 40g

0.001245 mole of NaOH = 40 × 0.001245 = 0.0498g

⇒0.0498g of NaOH was used during the titration

∴Mass concentration (g/L) = 0.0498g ÷ 0.02L

= 2.49g/L.

3 0

3 years ago

8

love history [14]

Answer : The molar concentration of sucrose in the tea is, 0.0549 M

Explanation : Given,

Mass of sucrose = 3.765 g

Volume of solution = 0.200 L

Molar mass of sucrose = 342.3 g/mole

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

$\text{Molarity}=\frac{\text{Mass of sucrose}}{\text{Molar mass of sucrose}\times \text{Volume of solution (in L)}}$

Now put all the given values in this formula, we get:

$\text{Molarity}=\frac{3.765g}{342.3g/mole\times 0.200L}=0.0549mole/L=0.0549M$

Therefore, the molar concentration of sucrose in the tea is, 0.0549 M

7 0

3 years ago

What is the pOH of a 2.6 x 10-6 M H+ solution?

scZoUnD [109]

Answer:

pH = -log 2.6 x 10-6 M

pH = 5.585

pOH= 14 - 5.585 = 8.415

8.4 as 2 sig figs

8 0

3 years ago

A scientist finds an organism that cannot move. It has many cells and get food from its environment. In which Kingdom does it

Allisa [31]

An organism that does not move on its own and makes food from its environment is a producer.

7 0

3 years ago

The laws of electrostatics predict that protons will

GaryK [48]

The laws of the electrostatics were developed by Coulomb and are further detailed or subdivided into two as follows:

(1) The first one talks about the similarities in the charges of the particles and what happens to them. This states that like charges repel.

(2) The second one quantifies the field between two particles with equation showing that field is directly proportional to the masses and inversely to the square of the distance between them.

In this item, we can then say that the protons (having the same charges) will have to repel from each other in accordance to statement 1 of the law.

3 0

3 years ago