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aliya0001 [1]
2 years 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]2 years 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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A container is filled with helium gas. It has a volume of 2.25 liters and contains 9.00 moles of helium. How many moles of heliu
Darina [25.2K]

Answer: There are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.

Explanation:

Given: V_{1} = 2.25 L,     n_{1} = 9.0 mol

V_{2} = 1.85 L,            n_{2} = ?

Formula used to calculate the moles of helium are as follows.

\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\

Substitute the values into above formula as follows.

\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\\frac{2.25 L}{9.0 mol} = \frac{1.85 L}{n_{2}}\\n_{2} = \frac{1.85 L \times 9.0 mol}{2.25 L}\\= 7.4 mol

Thus, we can conclude that there are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.

7 0
2 years ago
The electron configuration belonging to the atom with the highest second ionization energy is ________.
Gemiola [76]

Answer:

Element Lithium

Explanation:

The element with the highest second ionization energy is lithium. It belongs to the alkaline metal group I.e group one metals

It has the highest second ionization energy because it is very difficult to remove the electron from the 1s orbital.

Its atomic number is 3. The electronic configuration is 1s2 2S1

5 0
3 years ago
What are the 5 areas of chemistry
shepuryov [24]
The 5 main branches of chemistry are physics, analytical, biochemistry, organic chemistry, and inorganic chemistry.
7 0
3 years ago
The reaction for photosynthesis producing glucose sugar and oxygen gas is:
uranmaximum [27]

Answer:

a. 1.12 L

Explanation:

Step 1: Write the balanced equation for the photosynthesis

6 CO₂(g) + 6 H₂O(l) ⇒ C₆H₁₂O₆(s) + 6 O₂(g)

Step 2: Calculate the moles corresponding to 2.20 g of CO₂

The molar mass of CO₂ is 44.01 g/mol.

2.20 g × 1 mol/44.01 g = 0.0500 mol

Step 3: Calculate the moles of O₂ produced

The molar ratio of CO₂ to O₂ is 6:6. The moles of O₂ produced are 6/6 × 0.0500 mol = 0.0500 mol

Step 4: Calculate the volume occupied by 0.0500 moles of O₂ at STP

At STP, 1 mole of O₂ occupies 22.4 L.

0.0500 mol × 22.4 L/1 mol = 1.12 L

4 0
3 years ago
While doing a distillation, Farha heats the mixture too fast, and the temperature rises too quickly. If the mixture is composed
Brums [2.3K]
D as the two substances could have close boiling points, so if the temperature is not controlled well, both substances will evaporate.
7 0
3 years ago
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