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3 years ago

The ph of a solution prepared by mixing 50.0 ml of 0.125 m naoh and 40.0 ml of 0.125 m hno3 is ________.

1 answer:

4 0

Both the acid and the base are known as strong substances which means they totally dissociate into ions in aqueous solution. Mixing the two a salt would be form which is NaNO3. The unreacted substances will be the one contributing to the pH of the solution.

0.125M HNO3 x 0.04L = 0.005 mol HNO3
0.125M NaOH x 0.05L = 0.00625 mol NaOH

As we can see, all of the HNO3 would react with NaOH so the remaining OH from the unreacted NaOH would be responsible for the pH.

0.00625 - 0.005 / ( 0.0500L + 0.0400L ) = 0.0139 M

pOH = -log( OH- ) 
pOH = 1.86 
pH = 14.00 - pOH 
pH = 12.14

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2 Zn + O2 → 2 ZnO

meriva

Answer:

we need 6.0 moles of zinc (Zn)

Explanation:

Step 1: Data given

Number of moles ZnO produced = 6.0 moles

Step 2: The balanced equation

2 Zn + O2 → 2 ZnO

For 2 moles Zinc we need 1 mol Oxygen to produce 2 moles Zinc oxide

Step 3: Calculate moles zinc

For 2 moles Zn we need 1 mol O2 to produce 2 moles ZnO

For 6.0 moles 2nO produced, we need 6.0 moles of zinc (Zn) and 3.0 moles of O2 to react.

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3 years ago

When I2 and FeCl2 are mixed together, iodine (I) cannot replace chlorine (Cl) in the compound because iodine is lower on the per

Nata [24]

Answer: The given statement is true.

Explanation: If this reaction would have occurred, then this reaction would be considered as displacement reaction.

Displacement reactions are the reaction in which more reactive element displaces the less reactive element in a chemical reaction. This is based on the reactivity of elements.

Reactivity of elements is the tendency of the elements to gain or loose electrons. The reactivity decreases down the group in a periodic table.

In the given reaction, Iodine and chlorine are the elements of the same group in the periodic table and iodine lies below chlorine in the group. So, the reactivity of iodine is less than the reactivity of chlorine.

Hence, in the given reaction, iodine will not replace chlorine because it lies below in the periodic table.

$FeCl_2+I_2\rightarrow \text{No reaction}$

3 0

3 years ago

In ____________ reactions, certain molecules are broken down; in the process they release energy which is captured when high-ene

Rudik [331]

Answer:

Exergonic ,Endergonic,low concentration area,high

Explanation:

In exergonic reaction,certain molecules are broken down;in the process they release energy which is captured when high energy molecules(such as ATP and NADH) are formed.

The breakdown of these molecules can be coupled to thermodynamically unfavorable processes such as Endergonic reactions or pumping og hydrogen ion from low concentration areas to high concentration areas.

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2 years ago

Consider an element Z that has two naturally occuring isotopes with the following percent abundances: the isotope with a mass nu

rodikova [14]

Answer:

Z=22.70

Explanation:

It is given that,

An element Z that has two naturally occurring isotopes with the following percent abundances as follows :

The isotope with a mass number 22 is 65.0% abundant; the isotope with a mass number 24 is 35.0% abundant.

The average atomic mass for element Z is given by :

$Z=\dfrac{22\times 65+24\times 35}{100}\\\\Z=22.7$

So, the average atomic mass for element Z is 22.70.

3 0

3 years ago

How many moles of H2O are needed to produce 5.6 mol of NaOH? Na2O + H2O --> 2NaOH

navik [9.2K]

Answer: 2.8 moles

Explanation:

The balanced equation below shows that 1 mole of sodium oxide reacts with 1 mole of water to form 2 moles of sodium hydroxide respectively.

Na2O + H2O --> 2NaOH

1 mole of H2O = 2 moles of NaOH

Let Z moles of H2O = 5.6 mole of NaOH

To get the value of Z, cross multiply

5.6 moles x 1 mole= Z x 2 moles

5.6 = 2Z

Divide both sides by 2

5.6/2 = 2Z/2

2.8 = Z

Thus, 2.8moles of H2O are needed to produce 5.6 mol of NaOH

3 0

2 years ago