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3 years ago

Which combinations of substances resulted in a chemical change?

1 answer:

8 0

Any chemical reaction would always result to a chemical change. If you can see observations of a change in color, bubbling or any liberation of gas, formation of a precipitate, or a change in temperature, then a chemical change has occurred. I can't say which combinations would result to a chemical change because there are no choices. I can only give an example. If HCl reacts with NaOH,

HCl + NaOH → NaCl + H₂O

This is a chemical change because a precipitate in the form of NaCl salt is formed.

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The two common chlorides of phosphorus, PCl3, and PCl5, both important for the production of the other phosphorus compounds, coe

Irina18 [472]

Answer:

For a: The value of $K_c$ for the given reaction is 271.6

For b: The value of $K_p$ for the reaction is 6.32

Explanation:

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

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

For $PCl_5$ :

Given mass of $PCl_5$ = 0.105 g

Molar mass of $PCl_5$ = 208.24 g/mol

Putting values in equation 1, we get:

$\text{Moles of }PCl_5=\frac{0.105g}{208.24g/mol}=5.04\times 10^{-4}mol$

For $PCl_3$ :

Given mass of $PCl_3$ = 0.220 g

Molar mass of $PCl_5$ = 137.33 g/mol

Putting values in equation 1, we get:

$\text{Moles of }PCl_3=\frac{0.220g}{137.33g/mol}=1.60\times 10^{-3}mol$

For $Cl_2$ :

Given mass of $Cl_2$ = 2.12 g

Molar mass of $Cl_2$ = 71.0 g/mol

Putting values in equation 1, we get:

$\text{Moles of }Cl_2=\frac{2.12g}{71.0g/mol}=0.029mol$

Volume of the flask = 25.0 L

For the given chemical equation:

$PCl_3(g)+Cl_2(g)\rightleftharpoons PCl_5(g)$

For a:

The equation used to calculate concentration of a solution is:

$\text{Molarity}=\frac{\text{Moles}}{\text{Volume (in L)}}$

The expression of $K_c$ for above reaction follows:

$K_c=\frac{PCl_5}{PCl_3\times Cl_2}$

We are given:

$[PCl_5]=\frac{5.04\times 10^{-4}mol}{25L}$

$[PCl_3]=\frac{1.60\times 10^{-3}mol}{25L}$

$[Cl_2]=\frac{0.029mol}{25L}$

Putting values in above equation, we get:

$K_c=\frac{(\frac{5.04\times 10^{-4}}{25})}{(\frac{1.60\times 10^{-3}}{25})\times (\frac{0.029}{25})}\\\\K_c=271.6$

Hence, the value of $K_c$ for the given reaction is 271.6

For b:

Relation of $K_p$ with $K_c$ is given by the formula:

$K_p=K_c(RT)^{\Delta ng}$

where,

$K_p$ = equilibrium constant in terms of partial pressure = ?

$K_c$ = equilibrium constant in terms of concentration = 271.6

R = Gas constant = $0.0821\text{ L atm }mol^{-1}K^{-1}$

T = temperature = $250^oC=250+273=523K$

$\Delta n_g$ = change in number of moles of gas particles = $n_{products}-n_{reactants}=1-2=-1$

Putting values in above equation, we get:

$K_p=271.6\times (0.0821\times 523)^{-1}\\\\K_p=6.32$

Hence, the value of $K_p$ for the reaction is 6.32

7 0

4 years ago

Equilibrium systems exist throughout nature. True or False??

Natali5045456 [20]

I think the answer is true

6 0

4 years ago

Read 2 more answers

It’s about electron configuration

Goryan [66]

Answer:

True

Explanation:

A metal , has 1 electron on the last level, so it can become (A^+1)

C, non-metal, has 7 electrons on the last level, so it can become (C^-1)

Compound AC is possible

3 0

3 years ago

Atoms are so small that approximately _______ of them can fit at the end of a needle?

rewona [7]

Answer:

5 million million atoms can fit at the end of a needle

4 0

3 years ago

Read 2 more answers

PLEASE HELP ASAP

Inessa05 [86]

The enthalpy change for the reaction 2K + S + K2S using the following thermochemical reactions is mathematically given as

dn=70.7kg

<h3>What is the enthalpy change for the reaction?</h3>

Generally, the equation for the Chemical reaction is mathematically given as

2k+s----->K2S

Therefore

KS+K----->K2S

Therefore

dn=dn1+dn2

dn=32.5+38.2

dn=70.7kg

In conclusion, the enthalpy change is

dn=70.7kg