The process in which substances are changed into different substances is called

The normal freezing point of a certain liquid Xis-7.30°C but when l02. g of iron(III) chloride (FeCl3) are dissolved in 650. g o

IRISSAK [1]

Answer:

2.7 °C.kg/mol

Explanation:

Step 1: Calculate the freezing point depression (ΔT)

The normal freezing point of a certain liquid X is-7.30°C and the solution freezes at -9.9°C instead. The freezing point depression is:

ΔT = -7.30 °C - (-9.9 °C) = 2.6 °C

Step 2: Calculate the molality of the solution (b)

We will use the following expression.

b = mass of solute / molar mass of solute × kilograms of solvent

b = 102. g / (162.2 g/mol) × 0.650 kg = 0.967 mol/kg

Step 3: Calculate the molal freezing point depression constant Kf of X

Freezing point depression is a colligative property. It can be calculated using the following expression.

ΔT = Kf × b

Kf = ΔT / b

Kf = 2.6 °C / (0.967 mol/kg) = 2.7 °C.kg/mol

7 0

3 years ago

How do you prove law of conservation of mass??

Cerrena [4.2K]

The Law of Conservation of Mass<span> states that </span>matter <span>can neither be created nor destroyed in a chemical reaction.</span>

3 0

4 years ago

Extra Stoichiometry Practice

Irina-Kira [14]

Answer: 50. 4g

Explanation:

First calculate number of moles of aluminium in 38.8g

Moles = 38.8g/ 26.982mol/g

= 1.44mol

By looking at the balance equation you can see that 4 moles of aluminium produce 2 moles of aluminium oxide.

4 = 2

1.4 = x

Find the value of x

x= (1.4×2)/4= 0.72 mol

0.72 moles of aluminium oxide are produced from 38.8g of aluminium

Now find the mass of aluminium produced.

Mass = moles × molar mass

= 0.72mol × 69.93 mol/g

= 50.4g

8 0

3 years ago

Please Balanced this Equation

Scilla [17]

Answer:

$\rm {Cr_2O_7}^{2-} + 6 \; Fe^{2+} + \underbrace{\rm 14\; H^{+}}_{\text{From}\atop \text{Acid}}\to 2\; Cr^{3+} + 6\; Fe^{3+} + 7\; H_2 O$ .

Explanation:

Consider the oxidation state on each of the element:

Left-hand side:

O: -2 (as in most compounds);
Cr: $\displaystyle \frac{1}{2}(\underbrace{-2}_{\text{ion}} - \underbrace{7\times (-2)}_{\text{Oxygen}}) = +6$ ;
Fe: +2 (from the charge of the ion);

Right-hand side:

Cr: +3;
Fe: +3.

Change in oxidation state:

Each Cr atom: decreases by 3 (reduction).
Each Fe atom: increases by 1 (oxidation).

Changes in oxidation states shall balance each other in redox reactions. Thus, for each Cr atom on the left-hand side, there need to be three Fe atoms.

Assume that the coefficient of the most complex species $\rm Cr_2O_7^{2-}$ is 1. There will be two Cr atoms and hence six Fe atoms on the left-hand side. Additionally, there are going to be seven O atoms.

Atoms are conserved in chemical reactions. As a result, the right-hand side of this equation will contain

two Cr atoms,
six Fe atoms, and
seven O atoms.

O atoms seldom appear among the products in acidic environments; they rapidly combine with $\rm H^{+}$ ions to produce water $\rm H_2O$ . Seven O atoms will make seven water molecules. That's fourteen H atoms and hence fourteen $\rm H^{+}$ ions on the product side of this equation. Hence the balanced equation. Double check to ensure that the charges on the ions also balance.

$\rm {Cr_2O_7}^{2-} + 6 \; Fe^{2+} + \underbrace{\rm 14\; H^{+}}_{\text{From}\atop \text{Acid}}\to 2\; Cr^{3+} + 6\; Fe^{3+} + 7\; H_2 O$ .

7 0

3 years ago

Modify isoleucine, below, to show its structure at pH 1 and pH 13.

NeTakaya

I have attached the answer

remember that when the solution is acidic, pH lower than 7. there are extra H+ that the amino acid can take. the basic part of the amino acid takes this extra hydrogen (the nitrogen).

when the pH is higher than 7, basic, there are not much H+ available. the amino acid loses a H+. the acid part of the amino acid loses the H (the carboxylic part).

7 0

3 years ago