Convert 256.3 g sodium carbonate to formula units

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ikadub [295]

Answer:

A.

Explanation:

hope it helps...

4 0

2 years ago

Which phrase describes a valence electron?(1 point)

liraira [26]

Answer: I THINK C

Explanation: It has a 25% chance of being right so I'd wait if I were you just sayin

3 0

2 years ago

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Naturally occurring element X exists in three isotopic forms: X-28 (27.979 amu, 92.21% abundance), X-29 (28.976 amu 4.70% abunda

bezimeni [28]

Answer: The average atomic mass of X is 28.09 amu

Explanation:

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$ .....(1)

For isotope 1:

Mass of isotope 1 = 27.979 amu

Percentage abundance of isotope 1 = 92.21 %

Fractional abundance of isotope 1 = 0.9212

For isotope 2:

Mass of isotope 2 = 28.976 amu

Percentage abundance of isotope 2 = 4.70 %

Fractional abundance of isotope 2 = 0.0470

For isotope 3:

Mass of isotope 3 = 29.974 amu

Percentage abundance of isotope 3 = 3.09 %

Fractional abundance of isotope 3 = 0.0309

Putting values in equation 1, we get:

$\text{Average atomic mass of X}=[(27.979\times 0.9212)+(28.976\times 0.0470)+(29.974\times 0.0309)]$

$\text{Average atomic mass of X}=28.09amu$

Hence, the average atomic mass of X is 28.09 amu

4 0

3 years ago

At-57 °C and 1 atm, carbon dioxide is in which phase? View Available Hint(s) Phase diagrams for water (Figure 1)and carbon dioxi

goblinko [34]

Answer:

Gas

Increase the pressure

Explanation:

Let's refer to the attached phase diagram for CO₂ (not to scale).

At -57 °C and 1 atm, carbon dioxide is in which phase?

If we look at the intersection between -57°C and 1 atm, we can see that CO₂ is in the gas phase.

At 10°C and 2 atm carbon dioxide is in the gas phase. From these conditions, how could the gaseous CO₂ be converted into liquid CO₂?

Since at 10°C and 2 atm carbon dioxide is below the triple point, the only way to convert it into liquid is by increasing the pressure (moving up in the vertical direction).

4 0

3 years ago

1. Which of the following is a correctly written thermochemical equation?

WITCHER [35]

Explanation:

1. Thermochemical equation is balance stoichiometric chemical equation written with the phases of the reactants and products in the brackets along with the enthalpy change of the reaction.

The given correct thermochemical reactions are:

$Fe(s)+O_2(g)\rightarrow Fe_2O_3(s),\Delta H = 3,926 kJ
$

$C_3H_8(g)+5O_2 (g)\rightarrow 3CO_2 (g)+4H_2O(l),\Delta H= 2,220 kJ/mol$

2. Phase change affect the value of the enthalpy change of the thermochemical equation. This is because change in phase is accompanied by change in energy. For example:

$H_2O(s)\rightarrow H_2O(g),\Delta H_{s}=51.1 kJ/mol$

$H_2O(l)\rightarrow H_2O(g),\Delta H_{v}=40.65 kJ/mol$

In both reaction phase of water is changing with change in energy of enthalpy of reaction.

7 0

3 years ago

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