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1 year ago

Which TWO observations are evidence that a chemical change is happening?

Chemistry

1 answer:

Kryger [21]1 year ago

7 0

Answer: it is B and D light

Explanation: when a spark happens that is changing and bubbles is also changing

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How do you balance a chemical equation

Dominik [7]

There should be mass balance and the charge balance between the reactants and the products

Mass balance : total no of individual atoms of each type should be balanced before and after the reaction

Charge balance : Overall charge of the reactants should be balanced with the overall charge of the products

You can balance,

1)by just looking at it

2)by Algebraic method given above or

3)by the redox method

You need to know how to get the oxidation numbers in order to use the oxidation method

6 0

2 years ago

What is the main cause of earthquakes?

Ahat [919]

Answer:

movement in tectonic plates. or volcanic eruptions.

Explanation:

5 0

2 years ago

A sample of water contains 5.24x10^22 molecules. How many moles are in this sample?

Helga [31]

Answer:

0.087 moles of water

Explanation:

Given data:

Number of molecules of water = 5.24×10²² molecules

Number of moles of water = ?

Solution:

The given problem will solve by using Avogadro number.

1 mole = 6.022 × 10²³ molecules of water

5.24×10²² molecules × 1 mol / 6.022 × 10²³ molecules

0.87×10⁻¹ mol

0.087 mol

Avogadro number:

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.

8 0

2 years ago

How many valence electrons does Carbonic Acid contain?

geniusboy [140]

4 carbon electrons. Hope this helps have a nice day

6 0

2 years ago

Consider two concentric spheres whose radii differ by t = 1 nm, the "thickness" of the interface. At what radius (in nm) of sphe

Gala2k [10]

Answer:

Radius of the interior sphere = 3.847 nm

Explanation:

The volume of the shell (Vs) is equal to the difference of the volume of the outer sphere (Vo) and the volume of the inner sphere (Vi). Then:

$V_s=V_o-V_i=V_i\\V_o=2*V_i\\$

If we express the radius of the outer sphere (ro) in function of the radius of the inner sphere (ri), we have (e being the shell thickness):

$r_o=r_i+e$

The first equation becomes

$\frac{4 \pi}{3}*r_o^{3} = 2 * \frac{4 \pi}{3}*r_i^{3} \\\\\frac{4 \pi}{3}*(r_i+e)^{3} = 2 * \frac{4 \pi}{3}*r_i^{3} \\\\(r_i+e)^{3} = 2 *r_i^{3} \\\\(r_i^{3}+3r_i^{2}e+3r_ie^{2}+e^{3})=2r_i^{3}\\\\-r_i^{3}+3r_i^{2}e+3r_ie^{2}+e^{3}=0\\\\-r_i^{3}+3r_i^{2}+3r_i+1=0$

To find ri that satisfies this equation we have to find the roots of the polynomial.

Numerically, it could be calculated that ri=3.847 nm satisfies the equation.

So if the radius of the interior sphere is 3.847 nm, the volume of the interior sphere is equal to the volume of the shell of 1nm.

8 0

2 years ago