Ask question

Ask question

All categories

3 years ago

10

How many moles are present in 16.9 g of Al2O3?

2 answers:

daser333 [38]3 years ago

7 0

0.166 mol are present in 16.9 g of Al2O3.

Dahasolnce [82]3 years ago

4 0

<span>The number of moles in Al2O3 is .16575 moles</span>

You might be interested in

Flames are the heat and light energy that is release when the chemical bonds in a substance are broken. What provides the chemic

Tpy6a [65]

Answer is C:Wax Or B:Heat

8 0

3 years ago

Read 2 more answers

Use the data given below to construct a Born-Haber cycle to determine the second ionization energy of Ca. Δ H°(kJ) Ca(s)→Ca(g) 1

Drupady [299]

Answer : The value of second ionization energy of Ca is 1010 kJ.

Explanation :

The formation of calcium oxide is,

$Ca(s)+\frac{1}{2}O_2(g)\overset{\Delta H_f}\rightarrow CaO(s)$

$\Delta H_f^o$ = enthalpy of formation of calcium oxide = -635 kJ

The steps involved in the born-Haber cycle for the formation of $CaO$ :

(1) Conversion of solid calcium into gaseous calcium atoms.

$Ca(s)\overset{\Delta H_s}\rightarrow Ca(g)$

$\Delta H_s$ = sublimation energy of calcium = 193 kJ

(2) Conversion of gaseous calcium atoms into gaseous calcium ions.

$Ca(g)\overset{\Delta H_I_1}\rightarrow Ca^{+1}(g)$

$\Delta H_I_1$ = first ionization energy of calcium = 590 kJ

(3) Conversion of gaseous calcium ion into gaseous calcium ions.

$Ca^{+1}(g)\overset{\Delta H_I_2}\rightarrow Ca^{+2}(g)$

$\Delta H_I_2$ = second ionization energy of calcium = ?

(4) Conversion of molecular gaseous oxygen into gaseous oxygen atoms.

$O_2(g)\overset{\Delta H_D}\rightarrow OI(g)$

$\frac{1}{2}O_2(g)\overset{\Delta H_D}\rightarrow O(g)$

$\Delta H_D$ = dissociation energy of oxygen = $\frac{498}{2}=249kJ$

(5) Conversion of gaseous oxygen atoms into gaseous oxygen ions.

$O(g)\overset{\Delta H_E_1}\rightarrow O^-(g)$

$\Delta H_E_1$ = first electron affinity energy of oxygen = -141 kJ

(6) Conversion of gaseous oxygen ion into gaseous oxygen ions.

$O^-(g)\overset{\Delta H_E_2}\rightarrow O^{2-}(g)$

$\Delta H_E_2$ = second electron affinity energy of oxygen = 878 kJ

(7) Conversion of gaseous cations and gaseous anion into solid calcium oxide.

$Ca^{2+}(g)+O^{2-}(g)\overset{\Delta H_L}\rightarrow CaO(s)$

$\Delta H_L$ = lattice energy of calcium oxide = -3414 kJ

To calculate the overall energy from the born-Haber cycle, the equation used will be:

$\Delta H_f^o=\Delta H_s+\Delta H_I_1+\Delta H_I_2+\Delta H_D+\Delta H_E_1+\Delta H_E_2+\Delta H_L$

Now put all the given values in this equation, we get:

$-635kJ=193kJ+590kJ+\Delta H_I_2+249kJ+(-141kJ)+878kJ+(-3414kJ)$

$\Delta H_I_2=1010kJ$

Therefore, the value of second ionization energy of Ca is 1010 kJ.

6 0

3 years ago

a. How can one tell if a chemical reaction is balanced? (.5 point) b. What information does a complete ionic equation give that

evablogger [386]

Answer:

I think it's C

Explanation:

i think its c b3cause when you guess c always feels right

8 0

2 years ago

How many molecules are in 71.3 moles of H2O

Svetradugi [14.3K]

H2O molar mass= 18.02
Use Avogadro’s constant to convert moles into particles.
71.3x6.02x10^23=429.229
There are 429.229 molecules in 71.3 moles of H2O

4 0

3 years ago

When magnesium reacts with chlorine, the chlorine atom gain electrons. what happens to chlorine in this reaction?

Mrrafil [7]

Answer:

D

Explanation:

Reduction refers to gain in electrons. Hence it is D

Oxidation occurs when the element loses electrons. Hence A is wrong

7 0

3 years ago