All categories

3 years ago

Please help me, Thank you!

Chemistry

1 answer:

Phantasy [73]3 years ago

3 0

Answer:

Explanation:

The atom shown in the image has 2 core electrons.

Electrons are the negatively charged particles within an atom. Therefore the total number of electrons surrounding the nucleus in the given specie is 7.

So;

We have 2 core electrons

And 5 valence electrons

The core electrons are the inner orbital electrons.

The valence electrons are the outermost electrons.

You might be interested in

The ph of a solution containing 0.818 M acetic acid<br> (ka1.76*10-5) ans 0.172 M sodium acetate is?

kvasek [131]

Explanation:

It is known that the relation between pH and $pK_{a}$ is as follows.

pH = $pK_{a} + log \frac{[salt]}{[acid]}$

and, $pK_{a} = -log K_{a}$

Hence, first we will calculate the value of $pK_{a}$ as follows.

$pK_{a} = -log K_{a}$

= $-log (1.76 \times 10^{-5}$

= 4.75

Now, we will calculate the value of pH as follows.

pH = $pK_{a} + log \frac{[\text{sodium acetate}]}{\text{acetic acid}}$

= $4.75 + log \frac{0.172}{0.818}$

= 4.75 + (-0.677)

= 4.07

Therefore, we can conclude that the pH of given solution is 4.07.

5 0

3 years ago

Building block of all matter is what<br>please help

babunello [35]

Atoms are the building blocks of all matter

8 0

3 years ago

Read 2 more answers

A student ran the following reaction in the laboratory at 671 K: 2NH3(g) N2(g) + 3H2(g) When she introduced 7.33×10-2 moles of N

vaieri [72.5K]

Answer:

Kc = 8.05x10⁻³

Explanation:

This is the equilibrium:

2NH₃(g) ⇄ N₂(g) + 3H₂(g)

Initially 0.0733

React 0.0733α α/2 3/2α

Eq 0.0733 - 0.0733α α/2 0.103

We introduced 0.0733 moles of ammonia, initially. So in the reaction "α" amount react, as the ratio is 2:1, and 2:3, we can know the moles that formed products.

Now we were told that in equilibrum we have a [H₂] of 0.103, so this data can help us to calculate α.

3/2α = 0.103

α = 0.103 . 2/3 ⇒ 0.0686

So, concentration in equilibrium are

NH₃ = 0.0733 - 0.0733 . 0.0686 = 0.0682

N₂ = 0.0686/2 = 0.0343

So this moles, are in a volume of 1L, so they are molar concentrations.

Let's make Kc expression:

Kc= [N₂] . [H₂]³ / [NH₃]²

Kc = 0.0343 . 0.103³ / 0.0682² = 8.05x10⁻³

3 0

3 years ago

What features did you use to classify igneous rocks as extrusive or intrusive ?

umka21 [38]

Answer: Igneous rocks may be simply classified according to their chemical/mineral composition as felsic, intermediate, mafic, and ultramafic, and by texture or grain size: intrusive rocks are course grained (all crystals are visible to the naked eye) while extrusive rocks may be fine-grained (microscopic crystals) or glass.

Explanation: Hope this helped! :)

6 0

3 years ago

Read 2 more answers

A compound is 2.00% H by mass, 32.7% S by mass, and 65.3% O by mass. What is its empirical

Katarina [22]

Answer:

empirical formula: $H_2SO_4$

2 g H

32.7 g S

65.3 g O

Explanation:

Like the problem said, the first thing we can do is calculate the mass of each of the 3 elements in a 100-gram sample:

- 2.00% * 100g = 2 g H

- 32.7% * 100g = 32.7 g S

- 65.3% * 100g = 65.3 g O

Now we need to find the empirical formula from these. To do so, convert all of those masses into moles by using the molar mass for each element:

- the molar mass of H is 1.01 g/mol

- the molar mass of S is 32.06 g/mol

- the molar mass of O is 16 g/mol

2 g H ÷ 1.01 g/mol = 1.98 mol H

32.7 g S ÷ 32.06 g/mol = 1.02 mol S

65.3 g O ÷ 16 g/mol = 4.08 mol O

Our ratio of H : S : O is now:

1.98 mol : 1.02 mol : 4.08 mol

Divide them all by the smallest number, which is 1.02:

1.98/1.02 : 1.02/1.02 : 4.08/1.02

1.94 : 1 : 4

1.94 ≈ 2

So:

2 : 1 : 4

Thus, the empirical formula is: $H_2SO_4$ .

7 0

3 years ago