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2 years ago

45. most abundant metal in the earth's crust 46. first discovered in light coming from the sun

Chemistry

1 answer:

Yanka [14]2 years ago

3 0

Answer:

45. Aluminum

46. helium

Explanation:

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What is the mass in 0.25 mol of SO2

gulaghasi [49]

0.25 mols SO₂ x 64.058 g SO₂/ 1 mol SO₂ = 16.0145 g SO₂

molar mass of SO₂: 64.058 g

answer: 16 grams of SO₂ (2 sig figs)

check the question to see if its asked for a specific unit for mass (grams or kilograms, if they asked for kiligrams then convert 16 grams to kilograms by dividing it by 1000)

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3 years ago

One peanut M&M weighs approximately 2.33 g.

Sphinxa [80]

Answer:

There are 23076 peanut M&M's in 53.768 kg of M&M's.

Explanation:

First we convert 53.768 kg into g:

53.768 kg * 1000 = 53768 g

Then we divide the total mass of M&M's by the mass of one peanut M&M, in order to calculate the answer:

53768 g / 2.33 g = 23076

So there are 23076 peanut M&M's in 53.768 kg of M&M's.

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2 years ago

A general term for a chemical which accelerates a reaction without becoming chemically involved is called a catalyst. true false

BARSIC [14]

As long as the chemical is not used up in the reaction the answer is true

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2 years ago

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What do atoms when they share electron pairs

ra1l [238]

Covalent bonds I think

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2 years ago

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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 $2.728\times 10^{-15}J$

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2 years ago