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3 years ago

Calculate the mass percent (m/m) of a solution prepared by dissolving 55.84 g of nacl in 152.7 g of h2o.

1 answer:

7 0

M(NaCl)=55.84 g
m(H₂O)=157.2 g

m(solution)=m(NaCl)+m(H₂O)

w(NaCl)=100m(NaCl)/m(solution)=100m(NaCl)/(m(NaCl)+m(H₂O))

w(NaCl)=100*55.84/(55.84+152.7)=26.78%

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Calculate the energy (in kJ) required to heat 10.1 g of liquid water from 55 oC to 100 oC and change it to steam at 100 oC. The

Maksim231197 [3]

Answer:

$\large\boxed{\large\boxed{24.6kJ}}$

Explanation:

1. Energy to heat the liquid water from 55ºC to 100ºC

$Q=m\times C\times \Delta T$

m = 10.1g

C = 4.18g/JºC

ΔT = 100ºC - 55ºC = 45ºC

$Q=10.1g\times 4.18J/g\ºC\times 45\ºC=1,899.81J$

2. Energy to change the liquid to steam at 100ºC

$L=\lambda \times n$

λ = 40.6kJ/mol

n = 10.1g / 18.015g/mol = 0.5606mol

$L=40.6kJ/mol\times 0.5604mol=22.76214kJ=22,762.14J$

3. Total energy

$1,899.81J+22,762.14J=24,661.95J\approx24,662J\approx24.6kJ$

7 0

3 years ago

Electronic and electrical devices differ in the way they use _____.

Katena32 [7]

Election current because voltage is a measurement, information doesn't apply to all electrical devices and the wires within are usually copper bc it conducts and hardly ever will the wires be anything different because copper is cheap

3 0

2 years ago

Find the force of gravity of 1000 kg car.

ANEK [815]

Answer:

The force of gravity acting on the car is 9800 N vertically downward.

Explanation:

Given:

Mass of the car given is 1000 kg.

We know that the force of gravity is the force applied by the center of Earth on any body. The force of gravity is also called the weight of the body and always act towards the center of the Earth.

From Newton's second law, we know that the force acting on a body is equal to its mass and acceleration.

Here, the acceleration acting on the car is due to gravity and thus has a constant value of 9.8 m/s² on the surface of Earth.

Therefore, the force of gravity acting on the car is given using the Newton's second law as:

Force of gravity = Mass of car $\times$ Acceleration due to gravity.

Force of gravity = (1000 kg) $\times$ (9.8 m/s²)

Force of gravity = 9800 N [1 kg.m/s² = 1 N]

Therefore, the force of gravity acting on the car is 9800 N vertically downward.

6 0

2 years ago

Ammonia can be produced in the laboratory by heating ammonium chloride

AnnyKZ [126]

Answer:

Mass = 2.89 g

Explanation:

Given data:

Mass of NH₄Cl = 8.939 g

Mass of Ca(OH)₂ = 7.48 g

Mass of ammonia produced = ?

Solution:

2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃ + 2H₂O

Number of moles of NH₄Cl:

Number of moles = mass/molar mass

Number of moles = 8.939 g / 53.5 g/mol

Number of moles = 0.17 mol

Number of moles of Ca(OH)₂ :

Number of moles = mass/molar mass

Number of moles = 7.48 g / 74.1 g/mol

Number of moles = 0.10 mol

Now we will compare the moles of ammonia with both reactant.

NH₄Cl : NH₃

2 : 2

0.17 : 0.17

Ca(OH)₂ : NH₃

1 : 2

0.10 : 2/1×0.10 = 0.2 mol

Less number of moles of ammonia are produced by ammonium chloride it will act as limiting reactant.

Mass of ammonia:

Mass = number of moles × molar mass

Mass = 0.17 mol × 17 g/mol

Mass = 2.89 g

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2 years ago

The temperature at which a liquid becomes a solid is the:

Olenka [21]

The answer is "c" because solidification or freezing is the term used for the process in which a liquid becomes a solid. Freezing is an exothermic process that also is an example of a phase transition

3 0

2 years ago