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Kipish [7]
3 years ago
8

How have chemists changed the periodic table over time?

Chemistry
1 answer:
mrs_skeptik [129]3 years ago
5 0

They have used added new elements to the  table .

<u>Explanation:</u>

As new elements are discovered chemists add them to the period table leading to the periodic table undergoing continuous modifications. When the first periodic table in the world was formed, very few elements were known to humankind. Earlier periodic tables thus contain lesser number of elements than the modern ones.

Mendeleev's periodic table contained 63 elements arranged in the increasing order of their atomic masses. Modern periodic tables have far more number then the older ones like that of Mendeleev's and the elements are arranged in the order of their atomic numbers.

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What is the formula for this ionic crystal?
Alex777 [14]

Answer:

Al₄O₅

Explanation:

    The key at the bottom tells us the blue spheres are oxygen atoms and the red spheres are aluminum atoms. By counting, there are 4 aluminum atoms and 5 oxygen atoms. Therefore, the formula is Al₄O₅.

6 0
3 years ago
Which is the correct equilibrium constant expression for the following reaction? Fe2O3(s) + 3H2(g) --&gt; 2Fe(s) + 3H2O(g) Kc =
svetlana [45]

Answer:

The equilibrium constant Kc = [Fe]²*[H2O]³ / [Fe2O3][H2]³

Explanation:

Step 1: Data given

For the reaction aA + bB ⇆ cC + dD

the equilibrium constant Kc = [C]^c * [D]^d/[B]^b*[A]^a

Step 2: The balanced equation

Fe2O3(s) + 3H2(g) --> 2Fe(s) + 3H2O(g)

Step 3: Calculate the equilibrium constant Kc

Kc =  [C]^c * [D]^d/[B]^b*[A]^a

⇒with [C] = [Fe]

⇒ with c = 2

⇒with [D] = [H2O]

⇒with d = 3

⇒with [A] = [Fe2O3]

⇒with a = 1

⇒with [B] = [H2]

⇒with b = 3

Kc =  [C]^c * [D]^d/[B]^b*[A]^a

Kc = [Fe]²*[H2O]³ / [Fe2O3][H2]³

The equilibrium constant Kc = [Fe]²*[H2O]³ / [Fe2O3][H2]³

6 0
3 years ago
Chemistry is the study of all of the following EXCEPT
ValentinkaMS [17]
B - projectile motion
4 0
3 years ago
Air is made up of different gases, such as oxygen, nitrogen, and car
tia_tia [17]

The correct option would be that oxygen, nitrogen, and carbon dioxide cannot react with one another.

<h3>Why air components cannot react</h3>

The components of atmospheric air, nitrogen, oxygen, carbon dioxide, etc., cannot react with one another because there is not enough energy in the atmosphere to set the reaction rolling.

For a reaction to take place, there must be enough energy to break the bonds in each air component. This is why the air components will not spontaneously react with one another, except during special events such as lightning and thunder.

More on air components can be found here: brainly.com/question/17288850

#SPJ1

7 0
2 years ago
What is the pOH of a 0.00037 M solution of barium hydroxide
ruslelena [56]

Answer: pOH = 3.13

Ba(OH)2 is a very basic substance. The general formula for pOH is - log(OH)

Barium Hydroxide produces 2 moles of OH for every mole of Ba(OH)2 present in the solution.


0.00037 M = 3.7 * 10^-4 Ba(OH)2 will produce 2 *0.00037 M of OH-

OH- = 2* 0.00037 = 0.00074

pOH = - log(0.00074) = 3.13


5 0
3 years ago
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