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2 years ago

Periodic table fill in the box :)

Chemistry

1 answer:

Natalija [7]2 years ago

6 0

Answer:

I took a screen shot of your image, and wrote on top of it!

Explanation:

Hope this helps! :)

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How much energy is released by the decay of 3 grams of 230Th in the following reaction 230 Th - 226Ra + "He (230 Th = 229.9837 g

Serhud [2]

Answer: The energy released for the decay of 3 grams of 230-Thorium is $2.728\times 10^{-15}J$

Explanation:

First we have to calculate the mass defect $(\Delta m)$ .

The equation for the alpha decay of thorium nucleus follows:

$_{90}^{230}\textrm{Th}\rightarrow _{88}^{226}\textrm{Ra}+_2^{4}\textrm{He}$

To calculate the mass defect, we use the equation:

Mass defect = Sum of mass of product - Sum of mass of reactant

$\Delta m=(m_{Ra}+m_{He})-(m_{Th})$

$\Delta m=(225.9771+4.008)-(229.9837)=1.4\times 10^{-3}amu=2.324\times 10^{-30}kg$

(Conversion factor: $1amu=1.66\times 10^{-27}kg$ )

To calculate the energy released, we use Einstein equation, which is:

$E=\Delta mc^2$

$E=(2.324\times 10^{-30}kg)\times (3\times 10^8m/s)^2$

$E=2.0916\times 10^{-13}J$

The energy released for 230 grams of decay of thorium is $2.0916\times 10^{-13}J$

We need to calculate the energy released for the decay of 3 grams of thorium. By applying unitary method, we get:

As, 230 grams of Th release energy of = $2.0916\times 10^{-13}J$

Then, 3 grams of Th will release energy of = $\frac{2.0916\times 10^{-13}}{230}\times 3=2.728\times 10^{-15}J$

Hence, the energy released for the decay of 3 grams of 230-Thorium is $2.728\times 10^{-15}J$

5 0

3 years ago

Calculate the energy required to melt 21 g of ice at 0 oC.

vladimir1956 [14]

We are given:

Mass of ice = 21 grams

The ice is already at 0°c, the temperature at which it melts to form water

Molar heat of fusion of Ice = 6.02 kJ/mol

Finding the energy required:

Number of moles of Ice:

Molar mass of water = 18 g/mol

Number of moles = given mass/ molar mass

Number of moles = 21 / 18 = 7/6 moles

Energy required to melt the given amount of ice:

Energy = number of moles * molar heat of fusion

Energy = (7/6) * (6.02)

Energy = 7.02 kJ OR 7020 joules

7 0

3 years ago

Which of these features is usually found where mountains exist next to the ocean?

Doss [256]

Fjords are usually found where mountains exist next to the ocean.

So the correct answer is C.

Hope this helps,

Davinia.

8 0

3 years ago

Read 2 more answers

What type of bonds hold the atoms together in polyatomic ions

IRISSAK [1]

This is a covalent bond, a bond in which atoms share electrons. Covalent bonding generally happens between nonmetals. Covalent bonding is the type of bond that holds together the atoms within a polyatomic ion. It takes two electrons to make a covalent bond, one from each bonding atom.

Mark as brainlist if correct please and have a blessed day!

8 0

3 years ago

What are three ways of the atmosphere is important to living things?

UNO [17]

1. Blocks Ultra violet rays that can be harmful.
2. Provides Oxygen, so we can live.
3. It blocks meteors from hitting Earth's surface.

7 0

3 years ago