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3 years ago

What is the valency of Al2O3 and why?

1 answer:

riadik2000 [5.3K]3 years ago

7 0

The valency of Al₂O₃ is 0 because each element in the compound has its outer most shell completely filled so it cannot obtain electrons of donate them since it is in its stable-most form.

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This boggled my brain plzzz help❤

Andrew [12]

A is combustion

B is Combination

C is double replacement

D is decomposition

E is combination

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3 years ago

Can someone help me with this? (WILL GIVE BRAINLIEST)

iragen [17]

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3 years ago

What is the concentration of a 1:10 dilution of a 2.5 M solution of NaCl? How would you prepare exactly 100 ml of such a solutio

Marina CMI [18]

Answer: The concentration of the solution is 0.25 M

Explanation:

Let the volume of solution of 2.5 M NaCl be 10 mL

We are given:

Dilution ratio = 1 : 10

So, the solution prepared will have a volume of = $\frac{10}{1}\times 1000=100mL$

To calculate the molarity of the diluted solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated NaCl solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted NaCl solution

We are given:

$M_1=2.5M\\V_1=10mL\\M_2=?M\\V_2=100mL$

Putting values in above equation, we get:

$2.5\times 10=M_2\times 100\\\\M_2=\frac{2.5\times 10}{100}=0.25M$

Hence, the concentration of the solution is 0.25 M

6 0

3 years ago

Which best describes an element?

Aleonysh [2.5K]

I think the answer is a pure substance

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3 years ago

A student is using a coffee-cup calorimeter to determine the enthalpy change of the endothermic reaction of two aqueous solution

Liula [17]

Answer:

See the answer below

Explanation:

First, it should be understood that an endothermic reaction is one that absorbs energy in the form of heat from the surrounding. The products of endothermic reactions usually have higher energy than their reactants. Hence, the ΔH° which is referred to as the enthalpy change is usually positive.

Forgetting to cover the coffee-cup calorimeter means some of the heat energy absorbed by the reactants would be exchanged back to the surroundings - a loss. It also means that the enthalpy change would be smaller compared to if the cup had been covered because some of the heat has been lost to the surrounding.

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3 years ago