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3 years ago

Which of the following would indicate that a chemical change might be occurring?

Chemistry

2 answers:

vitfil [10]3 years ago

4 0

D. Is the best indicator for a chemical change.

kari74 [83]3 years ago

3 0

Answer:

Two solutions are mixed, and a solid begins to appear

Explanation:

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The chemical equation below shows the decomposition of nitrogen triiodide (NI3) into nitrogen (N2) and iodine (I2). 2NI3 mc030-1

marin [14]

The balanced chemical reaction would be:

2NI3 = N2 + 3I2

We use the reaction above and the molar masses of the substances involved. We start with the initial amount of NI3 reactant.

3.58 g NI3 (1 mol NI3 / 394.71 g NI3) (3 mol I2 / 2 mol NI3) = 0.0136 mol I2

Therefore, option C is the answer.

7 0

3 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 $2.728\times 10^{-15}J$

5 0

3 years ago

PLEASE HELP ME WITH THISSSS!!!

Lilit [14]

16) you can tell which craters are younger by them being small and you can tell which craters are older by them being larger.

17) The larger craters experienced energetic impacts because they are simply larger in size which makes them being impacted.

Hope this was helpful have a nice day :)

4 0

3 years ago

Calculate the mass (in g) of 2.1 x 1024 atoms of W.

vfiekz [6]

Set up your units to algebraically cancel out the original unit, and end up with the units of the answer in the final numerator. We'll first convert to moles by using Avogadro's number, then the atomic mass of tungsten (W) from the periodic table, since the mass, in grams, of one mole of any element is the atomic mass number:
2.1x10∧24 atoms W x (1 mole/6.022x10∧23 atoms) x (183.84g/1 mole) = 641.089 grams
Since your given number has only two significant figures (2.1), your answer should also only express in 2 sig figs: 6.4x10∧2 grams

6 0

3 years ago

Describe what type of electron transfer happens between these two atoms.

Goryan [66]

Use socratic in the App Store I’m not sure but it will help!

5 0

3 years ago

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