How many atoms are in 68.44 grams

Density is given in ____. a. Pa/cm3 c. g/s2 b. N/m2 d. g/cm3 Please select the best answer from the choices provided A B C D

Ray Of Light [21]

Density is given in Mass/Volume so the answer is D

7 0

3 years ago

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Cryolite, Na3AlF6(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. Balance the equation f

dmitriy555 [2]

Answer: The mass of cryolite produced is 51.48 kg

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For aluminium oxide:

Given mass of aluminium oxide = 12.5 kg = 12500 g (Conversion factor: 1 kg = 1000 g)

Molar mass of aluminium oxide = 101.96 g/mol

Putting values in equation 1, we get:

$\text{Moles of aluminium oxide}=\frac{12500g}{101.96g/mol}=122.6mol$

For NaOH:

Given mass of NaOH = 55.4 kg = 55400 g

Molar mass of NaOH = 40 g/mol

Putting values in equation 1, we get:

$\text{Moles of NaOH}=\frac{55400g}{40g/mol}=1389mol$

For HF:

Given mass of HF = 55.4 kg = 55400 g

Molar mass of HF = 20 g/mol

Putting values in equation 1, we get:

$\text{Moles of HF}=\frac{55400g}{20g/mol}=2770mol$

For the given chemical reaction:

$Al_2O_3(s)+6NaOH(l)+12HF(g)\rightarrow 2Na_3AlF_6+9H_2O(g)$

By Stoichiometry of the reaction:

1 mole of aluminium oxide reacts with 6 moles of sodium hydroxide and 12 moles of HF.

So, 122.6 moles of aluminium oxide will react with $(6\times 122.6)=735.6mol$ of sodium hydroxide and $(12\times 122.6)=1471.2mol$ of HF

As, given amount of NaOH and HF is more than the required amount. So, they are considered as an excess reagent.

Thus, aluminium oxide is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of aluminium oxide produces 2 moles of cryolite

So, 122.6 moles of aluminium oxide will produce = $\frac{2}{1}\times 122.6=245.2mol$ of cryolite

Now, calculating the mass of cryolite by using equation 1:

Molar mass of cryolite = 209.94 g/mol

Moles of cryolite = 245.2 mol

Putting values in equation 1, we get:

$245.2mol=\frac{\text{Mass of cryolite}}{209.94g/mol}\\\\\text{Mass of cryolite}=(245.2mol\times 209.94g/mol)=51477.3g$

Converting this into kilograms, we use the conversion factor:

1 kg = 1000 g

So, $51477.3 g\times (\frac{1kg}{1000g})=51.48kg$

Hence, the mass of cryolite produced is 51.48 kg

7 0

2 years ago

Q05 the "atomic number" of an atom is determined by the number of ________ it has.

Alexxx [7]

The atomic number of an atom is determined by the number of protons it has..

It is also the whole number shown on the periodic table

6 0

3 years ago

How do i calculate the mass of CO2 emitted per Kj of heat produced in a combustion reaction?

Alexxandr [17]

methanol:

1 mole CH3 OH --> produces --> 1 mole CO2

1 mole CO2 has a molar mass of 44.01 gh/mole

your set up is:
(44.01 g CO2) / -726.5kJ = 0.06058g

your answer 0.06058 grams of CO2 produced per kJ released.

6 0

3 years ago

¿Cuál de las siguientes configuraciones globales corresponde a un elemento químico que se comporta como metal? 1 punto [He]2s2 2

yuradex [85]

Answer:

[Ne]3s2

Explanation:

ahora tenemos que mirar cada una de las configuraciones electrónicas de cada átomo de cerca antes de tomar una decisión.

considerando la configuración electrónica más externa de cada una de las especies mostradas;

para la primera configuración, ns2 np6 corresponde a un gas noble.

para la segunda configuración ns2 np3 corresponde a un elemento no metálico del grupo 5.

para la tercera configuración, ns2 corresponde a un elemento metálico del grupo 2.

para la cuarta configuración, ns2 np4 corresponde a un elemento no metálico del grupo 6

5 0

3 years ago