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3 years ago

Will mark as Brainliest.

Chemistry

1 answer:

xeze [42]3 years ago

3 0

Spontaneous reaction.

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Number the steps for balancing equations:

Natali5045456 [20]

Answer:

identify the atoms on each side

count the atoms on its side

use coefficients to increase the atoms on each side

check to make sure you have the same number of each type of atom on each side

3 0

2 years ago

Read 2 more answers

Calculate the molecular weight of a substance. In which the solution of this substance in the water has a concentration of 7 per

Eduardwww [97]

Answer : The molecular weight of a substance is 157.3 g/mol

Explanation :

As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.

Mass of solute = 7 g

Mass of solution = 100 g

Mass of solvent = 100 - 7 = 93 g

Formula used :

$\Delta T_f=i\times K_f\times m\\\\T_f^o-T_f=k_f\times\frac{\text{Mass of substance(solute)}\times 1000}{\text{Molar mass of substance(solute)}\times \text{Mass of water(solvent)}}$

where,

$\Delta T_f$ = change in freezing point

$T_f^o$ = temperature of pure water = $0^oC$

$T_f$ = temperature of solution = $-0.89^oC$

$K_f$ = freezing point constant of water = $1.86^oC/m$

m = molality

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

$(0-(-0.89))^oC=1.86^oC/m\times \frac{7g\times 1000}{\text{Molar mass of substance(solute)}\times 93g}$

$\text{Molar mass of substance(solute)}=157.3g/mol$

Therefore, the molecular weight of a substance is 157.3 g/mol

7 0

3 years ago

Calculate the change in temperature (ΔT) that occurs when 8000 J of energy (q) is used to heat up a mass (m) of 75 g of water. (

pickupchik [31]

Answer:

The change in temperature that occurs when 8000 J of heat is used by a mass 75 g of water is 25.4 °C

Explanation:

H = mc ΔT

m = 75 g

c = 4. 200 J/ g °C

H = 8000 J

ΔT =?

Rearranging the formula, making ΔT the subject of formula;

ΔT = H / m c

ΔT = 8000 / 75 * 4.200

ΔT = 8000 / 315

ΔT = 25.4 °C

8 0

3 years ago

Read 2 more answers

How many moles of al does 13.49 g of al represent?

Harlamova29_29 [7]

Use equation
number of moles= sample mass/molar mass

7 0

2 years ago

What is the mass of 5.00 moles of KaS04?

Varvara68 [4.7K]

Answer: D

Explanation:

I assume you meant $\text{K}_{2}\text{SO}_{4}$ .

The atomic mass of potassium is 39.0983 g/mol.
The atomic mass of sulfur is 32.065 g/mol.
The atomic mass of oxygen is 15.9994 g/mol.

So, the formula mass of potassium sulfate is 2(39.0983)+32.065+4(15.9994)=174.2592 g/mol.

So, 5.00 moles have a mass of (5.00)(174.2592), which is about <u>870 g</u>

7 0

2 years ago