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aliya0001 [1]
1 year ago
15

Lawrencium-262 has a half-life of 4 hr. How much of a 40 mg sample remains after 12 hours?

Chemistry
1 answer:
CaHeK987 [17]1 year ago
3 0

Answer:

5 mg

Explanation:

If one half life is 4 hours, then 3 half lives is 12 hours.

This means that the sample will decay to 1/8 of its original amount.

So, the answer is 40(1/8) = 5 mg.

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On the periodic table, the majority of elements are classified as
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8 0
2 years ago
Read 2 more answers
Nitrogen gas reacts with hydrogen gas to produce ammonia. How many liters of hydrogen gas at 95kPa and 15∘C are required to prod
viktelen [127]

Answer:

222.30 L

Explanation:

We'll begin by calculating the number of mole in 100 g of ammonia (NH₃). This can be obtained as follow:

Mass of NH₃ = 100 g

Molar mass of NH₃ = 14 + (3×1)

= 14 + 3

= 17 g/mol

Mole of NH₃ =?

Mole = mass /molar mass

Mole of NH₃ = 100 / 17

Mole of NH₃ = 5.88 moles

Next, we shall determine the number of mole of Hydrogen needed to produce 5.88 moles of NH₃. This can be obtained as follow:

N₂ + 3H₂ —> 2NH₃

From the balanced equation above,

3 moles of H₂ reacted to produce 2 moles NH₃.

Therefore, Xmol of H₂ is required to p 5.88 moles of NH₃ i.e

Xmol of H₂ = (3 × 5.88)/2

Xmol of H₂ = 8.82 moles

Finally, we shall determine the volume (in litre) of Hydrogen needed to produce 100 g (i.e 5.88 moles) of NH₃. This can be obtained as follow:

Pressure (P) = 95 KPa

Temperature (T) = 15 °C = 15 + 273 = 288 K

Number of mole of H₂ (n) = 8.82 moles

Gas constant (R) = 8.314 KPa.L/Kmol

Volume (V) =?

PV = nRT

95 × V = 8.82 × 8.314 × 288

95 × V = 21118.89024

Divide both side by 95

V = 21118.89024 / 95

V = 222.30 L

Thus the volume of Hydrogen needed for the reaction is 222.30 L

8 0
2 years ago
Calculate the equilibrium constant K for the following reaction: H2(g) +
SIZIF [17.4K]

Answer:

192.9

Explanation:

From the question,

Ke = [HCL]²/[H₂][CL₂].......................... Equation 1

Where Ke = Equilibrium constant.

Given: [HCL] = 0.0625 M, [H₂] = 0.0045 M, [CL₂] = 0.0045 M

Substitute these values into equation 1

Ke = (0.0625)²/(0.0045)(0.0045)

ke = (3.90625×10⁻³)/(2.025×10⁻⁵)

ke = 1.929×10²

ke = 192.9

Hence the equilibrium constant of the system = 192.9

5 0
3 years ago
12. Classify the following as conduction, convection or radiation. a. A steel mug kept near a stove becomes hot after some time.
Tpy6a [65]

A - convection

B - conduction

C - radiation

D - convection

8 0
3 years ago
Hi. I need help with this
Vlad1618 [11]

Factors that determine ionization energy:

  • Electronic Repulsion - If the electronic density decreases, the ionization energy with increase and vice versa. If an electron gets released, it decreases the electronic repulsion. This makes releasing another electron harder than the first on unless the electron that is being released comes from another energetic level.
  • # Of Energy Levels - The more energy cores that get filled up, the more ionization levels decrease. When we see the energy levels go from top to bottom, the ionization also go from most to least. This is why ionization occurs on the highest level.
  • Nuclear Charge - The higher the atomic number, the higher charge in the nuclei. This also makes the ionization energy higher as it increases from left to right of in other words, if the nuclear charge gets higer, the energy gets higher as well.

Factors that determine atomic volume:

  • How many protons are in the nucleus (nuclear charge)
  • How many energy levels carry electrons (electrons in outer energy level)

Best of Luck!

4 0
3 years ago
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