I really need help who ever has the time and skills plzzz help me

What is the one thing that happens in every chemical change?

Sedbober [7]

Answer:

Explanation:

Chemical reactions involve combining different substances. The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions. The particles of one substance are rearranged to form a new substance.

7 0

2 years ago

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Number 7 plz tysm guys

morpeh [17]

It is letter C: Continental crust is thicker than oceanic crust.

6 0

2 years ago

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Balance the folowing equation.<br> S + 02<br> ws<br> SO:

Rzqust [24]

Answer:

s+o2=so2

Explanation:

i hope it will help u

6 0

2 years ago

At a certain temperature, the solubility of N2 gas in water at 4.07 atm is 95.7 mg of N2 gas/100 g water . Calculate the solubil

sertanlavr [38]

Answer: Thus the solubility of $N_2$ gas in water, at the same temperature, if the partial pressure of gas is 10.0 atm is 235mg/100g.

Explanation:-

The Solubility of $N_{2}$ in water can be calculated by Henry’s Law. Henry’s law gives the relation between gas pressure and the concentration of dissolved gas.

Formula of Henry’s law, $C=k_{H}P$ .

$k_{H}$ = Henry’s law constant = ?

The partial pressure (P) of $N_{2}$ in water = 4.07 atm

\ $C= k_{H}\times P\\95.7mg=k_{H}\times 4.07$

$k_{H}=23.5$

At pressure of 10.0 atm

$C= k_{H}\times P\\C=23.5\times 10.0=235mg/100mg$

Thus the solubility of $N_2$ gas in water, at the same temperature, is 235mg/100g

6 0

2 years ago

antimony has two naturally occuring isotopes, sb121sb121 and sb123sb123 . sb121sb121 has an atomic mass of 120.9038 u120.9038 u

Luda [366]

Considering the definition of atomic mass, isotopes and atomic mass of an element, sb121 has a percent natural abundance of 0.5726 or 57.26% and sb123 has a percent natural abundance of 0.4284 or 42.84%.

<h3>Definition of atomic mass</h3>

The atomic mass is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.

<h3>Definition of isotope</h3>

Isotopes are the chemical elements in which atomic numbers are the same, but the number of neutrons is different.

<h3>Definition of atomic mass</h3>

The atomic mass of an element is the weighted average mass of its natural isotopes.

This is, the atomic masses of elements are usually calculated as the weighted average of the masses of the different isotopes of each element, considering the relative abundance of each of them.

<h3>Percent natural abundance of each isotope</h3>

In this case, antimony has two naturally occuring isotopes, sb121 and sb123. You know:

sb121 has an atomic mass of 120.9038 u.
sb121 has a percent natural abundance of x.
sb123 has an atomic mass of 122.9042 u.
sb123 has a percent natural abundance of 1 -x (or, what is the same, the abundance is 100% - x%, since both isotopes form 100% of the element.)
Antimony has an average atomic mass of 121.7601 u