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3 years ago

URGENT! Will give 20 points.

Chemistry

2 answers:

Nataly [62]3 years ago

7 0

Idk why but for some reason the picture isnt ahowing up

Katena32 [7]3 years ago

6 0

Answer:

there is no picture...

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For each of the following sets of elements, circle the element expected to be most electronegative and draw a box which is expec

Evgen [1.6K]

Answer: The element expected to be most electronegative is Ca.

The element expected to be least electronegative is K.

Explanation:

Electronegativity is defined as the property of an element to attract a shared pair of electron towards itself.

Down the group:

The size of an atom increases as we move down the group because a new shell is added and electron gets added up.

As, the size of an element increases, the valence electrons gets away from the nucleus. So, the attraction between the nucleus and the shared pair of electrons decreases

Hence, electronegativity decreases moving from top to bottom down a group

Across a period:

The size of an atom decreases as we move across the period because the electrons get added to the same shell and the nuclear charge keeps on increasing. Thus the electrons get more tightly held by the nucleus.

As, the size of an element decreases, the valence electrons come near to the nucleus. So, the attraction between the nucleus and the shared pair of electrons increases.

Hence, electronegativity increases moving across left to right in a period.

Thus as K, Sc and Ca are arranged across a period, the electronegativity order is K< Sc < Ca.

7 0

3 years ago

What is the theoretical yield of vanadium, in moles, that can be produced by the reaction of 1.0 mole of V2O5 with 4.0 moles of

IRINA_888 [86]

Answer:

Theoretical yield of vanadium = 1.6 moles

Explanation:

Moles of $V_2O_5$ = 1.0 moles

Moles of $Ca$ = 4.0 moles

According to the given reaction:-

$V_2O_5_{(s)} + 5Ca_{(l)}\rightarrow 2V_{(l)} + 5CaO_{(s)}$

1 mole of $V_2O_5$ react with 5 moles of $Ca$

Moles of Ca available = 4.0 moles

Limiting reagent is the one which is present in small amount. Thus, Ca is limiting reagent. (4.0 < 5)

The formation of the product is governed by the limiting reagent. So,

5 moles of Ca on reaction forms 2 moles of V

1 mole of Ca on reaction for 2/5 mole of V

4.0 mole of Ca on reaction for $\frac{2}{5}\times 4$ mole of V

Moles of V = 1.6 moles

<u>Theoretical yield of vanadium = 1.6 moles</u>

4 0

3 years ago

Classify each of the following as an exothermic or an endothermic reaction:

ira [324]

Equation a. C3H8(g) + O2(g) → CO2(g) + H2O(g) + 2220 kj
is endothermic. + 2220 kj
Equation b. 2 Na(s) + Cl2(g) → 2 NaCl(s) + 819kJ
is also endothermic since the overall energy change is positive. + 819kJ
The equation c. PCl5(g) + 67kj → PCl3(g) + Cl2(g) is endothermic since it requires anergy to proceed.

6 0

4 years ago

Read 2 more answers

22. What is a comet?

Lunna [17]

Answer:

A ball of ice blasted into outer space

Explanation:

It is a ball of ice that is going so fast it leaves a "tail"

4 0

3 years ago

What determines the order of the elements in the modern periodic table ?

Novay_Z [31]

The last electron on the outer most shell. or d oder of dere atomic no

7 0

3 years ago