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2 years ago

What is uranium made of? For a keynote (school)

1 answer:

7 0

Pure uranium is radioactive. It will react with most nonmetallic elements to make compounds. When it comes into contact with air, a thin, black layer of uranium oxide will form on its surface. Uranium-235 is the only naturally occurring isotope that is fissile.

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A 3.50 amp power supply is used to deposit chromium from a solution of CrCl3. How long will it take to deposit 100.0 grams of ch

Norma-Jean [14]

Explanation:

The given data is as follows.

Current (I) = 3.50 amp, Mass deposited = 100.0 g

Molar mass of Cr = 52 g

It is known that 1 faraday of electricity will deposit 1 mole of chromium. As 1 faraday means 96500 C and 1 mole of Cr means 52 g.

Therefore, 100 g of Cr will be deposited by "z" grams of electricity.

$z \times 52 g = 96500 \times 100 g$

z = $\frac{96500 \times 100 g}{52 g}$

= 185576.9 C

As we know that, Q = I × t

Hence, putting the given values into the above equation as follows.

Q = I × t

185576.9 C = $3.50 amp \times t$

t = 53021.9 sec

Thus, we can conclude that 100 g of Cr will be deposited in 53021.9 sec.

3 0

2 years ago

The. bond dissociation enthalpies of the H-H bond and the H-Cl bond are 435 kJ mol^-1 and 431 kJ mol^-1, respectively. The ΔHfO

Novay_Z [31]

The bond dissociation energy of the Cl - Cl bond is -958 kJ mol^-1.

<h3>What is the dissociation enthalpy?</h3>

Given that;

H-H bond energy = 435 kJ mol^-1

H-Cl bond energy = 431 kJ mol^-1

ΔHfO of HCL(g) = -92kJ mol^-1

Bond dissociation enthalpy of the Cl-Cl bond = x

-92 = 435 + 431 + x

x = -92 - (435 + 431)

x = -958 kJ mol^-1

Learn More about dissociation enthalpy:brainly.com/question/9998007?

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6 0

1 year ago

Gold is alloyed (mixed) with other metals to increase its hardness in making jewelry.

KiRa [710]

Answer:

A) 54.04%

B) 13-karat

Explanation:

A) From the problem we have

1) Mg + Ms = 9.40 g

2) Vg + Vs = 0.675 cm³

Where M stands for mass, V stands for volume, and g and s stand for gold and silver respectively.

We can rewrite the first equation using the density values:

3) Vg * 19.3 g/cm³ + Vs * 10.5 g/cm³ = 9.40

So now we have a system of two equations (2 and 3) with two unknowns:

We express Vg in terms of Vs:

Vg + Vs = 0.675 cm³

Vg = 0.675 - Vs

We replace the value of Vg in equation 3:

Vg * 19.3 + Vs * 10.5 = 9.40

(0.675-Vs) * 19.3 + Vs * 10.5 = 9.40

13.0275 - 19.3Vs + 10.5Vs = 9.40

-8.8 Vs + 13.0275 = 9.40

Vs = 0.412 cm³

Now we calculate Vg:

Vg + Vs = 0.675 cm³

Vg + 0.412 cm³ = 0.675 cm³

Vg = 0.263 cm³

We calculate Mg from Vg:

0.263 cm³ * 19.3 g/cm³ = 5.08 g

We calculate the mass percentage of gold:

5.08 / 9.40 * 100% = 54.04%

We multiply 24 by the percentage fraction:

24 * 54.04/100 = 12.97-karat ≅ 13-karat

4 0

2 years ago

there are 125 lima beans 56 garbanzo beans 39 kidney beans and 144 green peas in a container. find the percent by number of gree

Sauron [17]

39.6% of the beans are green beans

5 0

2 years ago

A buffer is composed of nh3 and nh4cl. How would this buffer solution control the ph of a solution when a small amount of a stro

Shkiper50 [21]

Answer:

According to Le-chatelier principle, equilibrium will shift towards left to minimize concentration of $OH^{-}$ and keep same equilibrium constant

Explanation:

In this buffer following equilibrium exists -

$NH_{3}(aq.)+H_{2}O(l)\rightleftharpoons NH_{4}^{+}(aq.)+OH^{-}(aq.)$

So, $OH^{-}$ is involved in the above equilibrium.

When a strong base is added to this buffer, then concentration of $OH^{-}$ increases. Hence, according to Le-chatelier principle, above equilibrium will shift towards left to minimize concentration of $OH^{-}$ and keep same equilibrium constant.

Therefore excess amount of $OH^{-}$ combines with $NH_{4}^{+}$ to produce ammonia and water. So, effect of addition of strong base on pH of buffer gets minimized.

5 0

3 years ago