Calculate the final temperature when 50 ml of water at 65 are added to 25 ml of water at 25

Discovered electrons have fixed amounts of energy and orbit the nucleus similar to planets? A. John dalton B. J.J. Thomson C. Er

Fantom [35]

I think is letter c thanks

6 0

3 years ago

The mole fraction of CO2 in a certain solution with H2O as the solvent is 3.6 × 10−4. What is the approximate molality of CO2 in

nataly862011 [7]

Answer: C) 0.020 m

Explanation:

Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.

$Molality=\frac{n\times 1000}{W_s}$

where,

n = moles of solute

$W_s$ = weight of solvent in g

Mole fraction of $CO_2$ is = $3.6\times 10^{-4}$ i.e. $3.6\times 10^{-4}$ moles of $CO_2$ is present in 1 mole of solution.

Moles of solute $(CO_2)$ = $3.6\times 10^{-4}$

moles of solvent (water) = 1 - $3.6\times 10^{-4}$ = 0.99

weight of solvent = $moles\times {\text {Molar mass}}=0.99\times 18=17.82g$

Molality = $\frac{3.6\times 10^{-4}\times 1000}{17.82g}=0.020$

Thus approximate molality of $CO_2$ in this solution is 0.020 m

5 0

3 years ago

Calculate the mass of water formed when 4g of methane is burnt in excess oxygen

wariber [46]

Answer:

Mass of water formed: 9g

Explanation:

Hope it helps you!

6 0

2 years ago

Becquerel placed photographic paper in a drawer with some radioactive rocks and discovered that the amount of exposure on the pa

jolli1 [7]

Becquerel did not discover that the amount of exposure on the paper was proportional to the amount of uranium that was present in the rocks

<h3>What is radioactivity?</h3>

The phenomenon of radioactivity was discovered by the French scientist Henri Becquerel in 1896 when he placed photographic paper in a drawer with some radioactive rocks.

We have to note that Becquerel did not discover that the amount of exposure on the paper was proportional to the amount of uranium that was present in the rocks hence the stetement is false.

Learn more about radioactivity: brainly.com/question/1770619?

5 0

2 years ago

Caleb has a 860-kilogram car sitting in his back yard, gathering rust.

emmasim [6.3K]

<h3>Answer:</h3>

A. 860 kg

<h3>Explanation:</h3>

To answer the question we need to understand that;

Mass refers to the amount of matter in an object.
Weight, on the other hand, refers to the gravitational pull of an object to a given surface.
Mass is measured using a spring balance.

We also need to know that;

The mass of an object remains constant every where irrespective of the gravitational acceleration.

Therefore, an object on the surface of the earth would have the same mass as on the surface of the moon.
In this case; the mass of the car remains the same on the outer space as on the back yard.

3 0

3 years ago

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