Is the dissolving process for most salts endothermic or exothermic?

The elements in Groups 1A(1) and 7A(17) are all quite reactive. What is a major difference between them?

matrenka [14]

The elements in Groups 1A(1) and 7A(17) are all quite reactive.

<h3>Major difference between Groups 1A(1) and 7A(17) : </h3>

Group 7's halogens, which are non-metal elements, become less reactive as you move down the group. In contrast to the alkali metals in Group 1 of the periodic table, this trend is the opposite. The most reactive element in Group 7 is fluorine.

Alkali metals are soft and reactive metals. They react vigorously with water and become more reactive. And other hand halogens are reactive non metals.

Elements of group 1A are known as alkali metals. Elements of this group are lithium, sodium, potassium, rubidium, cesium.
Reactivity increase down group 1 but decrease up group 7 this is because group 7 elements react by gaining an electron. As one move down the group, the amount of electron shielding increases, meaning that the electron is less attracted to the nucleus.

To know more about Groups 1A(1) and 7A(17) please click here :

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6 0

2 years ago

Why is the Universal Law of Gravitation is a scientific Law and not a theory?

scoundrel [369]

This is a law because it describes the force but makes not attempt to explain how the force works. A theory is an explanation of a natural phenomenon. Einstein's General Theory of Relativity explains how gravity works by describing gravity as the effect of curvature of four dimensional spacetime.

5 0

3 years ago

Suppose a 0.025M aqueous solution of sulfuric acid (H2SO4) is prepared. Calculate the equilibrium molarity of SO4−2. You'll find

FromTheMoon [43]

<u>Answer:</u> The concentration of $SO_4^{2-}$ at equilibrium is 0.00608 M

<u>Explanation:</u>

As, sulfuric acid is a strong acid. So, its first dissociation will easily be done as the first dissociation constant is higher than the second dissociation constant.

In the second dissociation, the ions will remain in equilibrium.

We are given:

Concentration of sulfuric acid = 0.025 M

Equation for the first dissociation of sulfuric acid:

$H_2SO_4(aq.)\rightarrow H^+(aq.)+HSO_4^-(aq.)$

0.025 0.025 0.025

Equation for the second dissociation of sulfuric acid:

$HSO_4^-(aq.)\rightarrow H^+(aq.)+SO_4^{2-}(aq.)$

<u>Initial:</u> 0.025 0.025

<u>At eqllm:</u> 0.025-x 0.025+x x

The expression of second equilibrium constant equation follows:

$Ka_2=\frac{[H^+][SO_4^{2-}]}{[HSO_4^-]}$

We know that:

$Ka_2\text{ for }H_2SO_4=0.01$

Putting values in above equation, we get:

$0.01=\frac{(0.025+x)\times x}{(0.025-x)}\\\\x=-0.0411,0.00608$

Neglecting the negative value of 'x', because concentration cannot be negative.

So, equilibrium concentration of sulfate ion = x = 0.00608 M

Hence, the concentration of $SO_4^{2-}$ at equilibrium is 0.00608 M

4 0

3 years ago

9. Diamonds and quartz crystals look very similar but diamonds cost considerably

zheka24 [161]

Natural diamonds are made very deep within earth's surface where high temperatures and pressure exist naturally, thus making them much more difficult to obtain, and making them a more expensive option that Swarovski Crystal.

8 0

3 years ago

What is the formula of a compound in which element y form ccp lattice and atom x occupy 1/3rd of tetrahedral voids

Kisachek [45]

Y : CCP : 4 atoms
X : tetrahedral voids would be 1/3 × 8 = 8/3

so formula would be Y12X8 or Y3X2 !!

5 0

4 years ago