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Sergeeva-Olga [200]
3 years ago
12

How to solve for enthalpy for changes​

Chemistry
1 answer:
Natasha_Volkova [10]3 years ago
7 0
Always use this method !!! always

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Calculate the lithium ion (Li+) concentration for a 0.821 M Li2S solution.
kondor19780726 [428]

The lithium ion[Li⁺]=1.642 M

<h3>Further explanation</h3>

Ionic compounds will dissociate into ions when dissolved in water. The strength of the dissociation depends on the strength of the electrolyte properties. The stronger it is, the more ions will dissociate

Reaction

Li₂S⇒2Li⁺+S²⁻

mol ratio Li₂S : Li⁺: S²⁻ = 1 : 2 : 1

so the lithium-ion (Li⁺) concentration :

\tt 2\times 0.821=1.642~M

6 0
2 years ago
A scientist has 207.45g of H2O in a beaker. How many water molecules are in the beaker?
Tasya [4]

Answer:

6.94 x 10²⁴molecules

Explanation:

Given parameters:

Mass of water  = 207.45g

Unknown:

Number of molecules  = ?

Solution:

To solve this problem, we must understand:

      1 mole of a substance  contains 6.02 x 10²³ molecules

Now, first find the number of moles of water;

 Number of moles  = \frac{mass}{molar mass}  

 Molar mass of water  = 2(1) + 16  = 18g/mol

  Number of moles  = \frac{207.45}{18}   = 11.53moles

So;

          1 mole of a substance  contains 6.02 x 10²³ molecules

       11.53moles of carbon dioxide will contain 11.53 x  6.02 x 10²³

                                                                 = 6.94 x 10²⁴molecules

4 0
2 years ago
Find the number of moles of water that can be formed if you have 134 mol of hydrogen gas and 62 mol of oxygen gas
CaHeK987 [17]
164. You have excess hydrogen- you need double the number of moles hydrogen as oxygen because water has two hydrogens and only one oxygen while both hydrogen gas and oxygen gas are diatomic. 

<span>Because oxygen is diatomic, you spit it in half and basically double the number of moles, tack on your excess hydrogen, and you have 164 moles of water. </span>

<span>Edit: Lets look at it in one more way, taking into account what a mole is: </span>

<span>A mole is Avogadro's Constant number of particles- or about 6.02x10^23. So, we can multiply the number of moles you have to figure out how many particles of each we have. You can skip this step, because we will convert back to moles, but its illustrative of the concept. </span>

<span>6.02x10^23 x 174 moles H2 = 1.05 x 10^26 particles H2 </span>
<span>6.02x10^23 x 82 moles O2 = 4.94 x 10^25 particles O2 </span>

<span>I'm going to take one more step here- take them out of diatomic form. This will double the number of particles of each. </span>

<span>2.10 x 10^26 particles H+ </span>
<span>9.88 x 10^25 particles O(2-) </span>

<span>Now, we know we need a 2:1 oxygen atom to hydrogen atom ration, so we devide and see oxygen is our limiting reagent. So, we have 9.88 x 10^25 single oxygen atoms, all of which will become water the hydr</span>
3 0
3 years ago
Students in Mr. Klein’s chemistry class are conducting an experiment to calculate the specific heat of a copper sample. Mr. Klei
NeX [460]
Percent error in team 1 value:
(0.392 - 0.385)/0.385  x 100
= 1.81%

Percent error in team 2 value:
(0.395 - 0.385)/0.385 x 100
= 2.60%

B. Team 2 has an unresolved issue in on their hands, resulting in greater than acceptable error.
4 0
2 years ago
Read 2 more answers
The densevapor iodinee heptafluoride reacts rapidly with water to give a mixture of periodic acid and hydrofluoric acid .
erma4kov [3.2K]

Explanation:

When iodine heptafluoride reacts rapidly with water to give a mixture of periodic acid and hydrofluoric acid. Reaction equation for the same is as follows.

       IF_{7} + 6H_{2}O \rightarrow H_{5}IO_{6} + 7HF

As it is given that there are 3.72 \times 10^{-2} moles of iodine heptafluoride are present. Molar mass of IF_{7} is 259.9 g/mol. Molar mass of HIO_{4} is 227.94 g/mol and molar mass of HF is 20.01 g/mol.

Now, according to the reaction equation 3.72 \times 10^{-2} M IF_{7} gives 3.72 \times 10^{-2} M H_{5}IO_{6}.

Also, the volume is given as 795 ml or 0.795 L (as 1 mL = 0.001 L).

Hence, calculate the concentration of H_{5}IO_{6} into the solution as follows.

              Concentration = \frac{\text{no. of moles}}{volume}

                                      = \frac{3.72 \times 10^{-2}}{0.795 L}

                                      = 4.7 \times 10^{-2} mol/L

or,                                   = 0.047 M

Now, as 1 mol of IF_{7} produces 7 mol HF. So, 7 \times 3.72 \times 10^{-2} = 26.04 \times 10^{-2} M HF.

Therefore, concentration of HF will be calculated as follows.

             Concentration of HF = \frac{0.2604}{0.795}

                                              = 0.33 M

Thus, we can conclude that concentration of periodic acid is 0.047 M and concentration of hydrofluoric acid is 0.33 M.    

8 0
2 years ago
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