CAN SOMEONE HELP ME!

How many grams of ethylene glycol (c2h6o2 must be added to 1.25 kg of water to produce a solution that freezes at -5.88 ∘c?

e-lub [12.9K]

The freezing point depression is calculated through the equation,
ΔT = (kf) x m
where ΔT is the difference in temperature, kf is the freezing point depression constant (1.86°C/m), and m is the molality. Substituting the known values,
5.88 = (1.86)(m)
m is equal to 3.16m

Recall that molality is calculated through the equation,
molality = number of mols / kg of solvent
number of mols = (3.16)(1.25) = 3.95 moles
Then, we multiply the calculated amount in moles with the molar mass of ethylene glycol and the answer would be 244.9 g.

6 0

2 years ago

I need help with the 2nd part first gets brainlist

mixer [17]

Answer:

7. 4H₂O

Elements: Hydrogen, Oxygen

Number of molecules: 4

Number of elements: 8 H, 4 O

Number of Atoms: 12

Explanation:

The elements are determined by the their symbol i.e. H = hydrogen.

The number of molecules is determined by the coefficient ( the number in front of everything, in this case 4).

The number of elements is determined by the coefficient and the subscripts. Multiply the coefficient by the subscript after each element. When there is no subscript, it is equal to 1. 4H₂ = 4x2 = 8; 4O = 4x1 = 4.

The number of atoms is all the individual elements added together. 8+4 = 12.

8 0

2 years ago

Liquid hexane

maks197457 [2]

Answer: The mass of $H_2O$ produced is 2.52 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

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

For hexane:

Given mass of hexane = 1.72 g

Molar mass of hexane = 86.18 g/mol

Putting values in equation 1, we get:

$\text{Moles of hexane}=\frac{1.72g}{86.18g/mol}=0.020mol$

For oxygen gas:

Given mass of oxygen gas = 8.0 g

Molar mass of oxygen gas= 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{8.0g}{32g/mol}=0.25mol$

The chemical equation for the combustion of hexane follows:

$2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O$

By stoichiometry of the reaction:

If 2 moles of hexane reacts with 19 moles of oxygen gas

So, 0.020 moles of hexane will react with = $\frac{19}{2}\times 0.020=0.19mol$ of oxygen gas

As the given amount of oxygen gas is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, hexane is considered a limiting reagent because it limits the formation of the product.

By the stoichiometry of the reaction:

If 2 moles of hexane produces 14 moles of $H_2O$

So, 0.020 moles of hexane will produce = $\frac{14}{2}\times 0.020=0.14mol$ of $H_2O$

We know, molar mass of $H_2O$ = 18 g/mol

Putting values in above equation, we get:

$\text{Mass of }H_2O=(0.14mol\times 18g/mol)=2.52g$

Hence, the mass of $H_2O$ produced is 2.52 g

4 0

3 years ago

Calculate the amount of energy , in Joules, required to raise the temperature of 15.5 g of liquid water from 0.00o C to 75.0 oC.

deff fn [24]

Answer:

10043.225 J

Explanation:

We'll begin by calculating the amount of heat needed to change ice to water since water at 0°C is ice. This is illustrated below:

Mass (m) = 15.5g

Latent heat of fussion of water (L) = 334J/g

Heat (Q1) =..?

Q1 = mL

Q1 = 15.5 x 334

Q1 = 5177 J

Next, we shall calculate the amount of heat needed to raise the temperature of water from 0°C to 75°C.

This is illustrated below:

Mass = 15.5g

Initial temperature (T1) = 0°C

Final temperature (T2) = 75°C

Change in temperature (ΔT) = T2 – T1 = 75 – 0 = 75°C

Specific heat capacity (C) of water = 4.186J/g°C

Heat (Q2) =?

Q2 = MCΔT

Q2 = 15.5 x 4.186 x 75

Q2 = 4866.225 J

The overall heat energy needed is given by:

QT = Q1 + Q2

QT = 5177 + 4866.225

QT = 10043.225 J

Therefore, the amount of energy required is 10043.225 J

8 0

3 years ago

This is a force that acts over a distance, can not be seen, and causes like poles to repel and opposite poles to attract. What i

algol [13]

Answer:

Magnetic Force

Explanation:

6 0

2 years ago

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