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3 years ago

How many formula units are present in 25.0 mol of sodium chloride

1 answer:

7 0

The way to work out formula units is to do the amount of moles (in this case 25) times by 6.022 x 10^23. so, the answer is 1.5055 x 10^25 formula units. hope this helps! (by the way ^ represents ‘to the power of’ because i cant get the smaller symbols on here)

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Using standard heats of formation, calculate the standard enthalpy change for the following reaction. 2H2S(g) 3O2(g)2H2O(l) 2SO2

Marizza181 [45]

Answer:

$\Delta _rH=-1124.14kJ/mol$

Explanation:

Hello!

In this case, since the standard enthalpy change for a chemical reaction is stood for the enthalpy of reaction, for the given reaction:

$2H_2S(g) +3O_2(g)\rightarrow 2H_2O(l) +2SO_2(g)$

We set up the enthalpy of reaction considering the enthalpy of formation of each species in the reaction at the specified phase and the stoichiometric coefficient:

$\Delta _rH=2\Delta _fH_{H_2O,liq}+2\Delta _fH_{SO_2,gas}-2\Delta _fH_{H_2S,gas}-3\Delta _fH_{O_2,gas}$

In such a way, by using the NIST database, we find that:

$\Delta _fH_{H_2O, liq}=-285.83kJ/mol\\\\\Delta _fH_{SO_2, gas}=-296.84kJ/mol\\\\\Delta _fH_{O_2,gas}=0kJ/mol\\\\\Delta _fH_{H_2S,gas}=-20.50kJ/mol$

Thus, we plug in the enthalpies of formation to obtain:

$\Delta _rH=2(-285.73kJ/mol)+2(-296.84kJ/mol)-2(-20.50kJ/mol)-3(0kJ/mol)\\\\\Delta _rH=-1124.14kJ/mol$

Best regards!

8 0

3 years ago

The dipole moment of the water molecule (H2O) is 6.17x10^-30 C.m. Consider a water molecule located at the origin whose dipole m

valkas [14]

Answer:

There are other details missing in the question. i.e Assume that x is much larger than the separation d between the charges in the dipole, so that the approximate expression for the electric field along the dipole axis E = p/2πε0y3 can be used, where p is the dipole moment, and y is the distance between ions. A) What is magnitude______N B) Direction? +x-direction or -x-direction C) Is this force attractive or repulsive?

A) Magnitude of electric force = 6.576 x 10 raised to power -13 N

B) Since the force direction is always dependent on the electric field and electric field = F/q, since the chlorine has a negative charge as such the direction of the electric force will be in the X - direction

C) Since the charges are of different nature, as such the force between them will be ATTRACTIVE.

Explanation:

The detailed steps is shown in the attachment

8 0

3 years ago

Summarize why the carbon cycle supports the Law of Conservation of Matter

sasho [114]

The Law of Conservation of Matter states that matter cannot be created or destroyed. The carbon cycle is an example of the Law because the same carbon atoms are being recycled through the carbon cycle. ... Carbon is used for energy, and some is stored for growth.

8 0

3 years ago

List 2 things that about Velocity and Speed that are Different and two that are the same.

frozen [14]

Hey there!
Speed and velocity both:
1) Measure how fast something is moving
2) Both measured in miles per hour, meters/second, etc (rates)
However, there's a prime difference:
Different because:
1) Velocity is speed, but in a certain direction
2) Velocity is a vector
3) Velocity can be positive <em>or</em> negative, unlike speed.
I added another just in case you had a preference :)

Hope this helps!

8 0

3 years ago

Which of the following organisms in the soil food chain does not obtain energy directly from plants?

aliina [53]

<span>The organisms in the soil food chain that don't obtain energy directly from plants are protozoa.
</span>

3 0

3 years ago

Read 2 more answers