All categories

3 years ago

What did johann wolfgang döbereiner contribute to the periodic table?

1 answer:

3 0

His work foreshadowed the periodic table. He tried organizing elements into triads, a set of 3 elements with similar properties. In each triad the mean of the lightest and heaviest atomic weight equaled to approximately the atomic weight of the middle element.

You might be interested in

Help with this please

Len [333]

Answer:

Explanation:

There are 4 sulfur atoms in SO4

4×3=12

This means that it turns into 3×(SO4)

=3SO4

6 0

3 years ago

Which is the most likely to be reduced?

NISA [10]

Answer : The correct option is, $Zn^{2+}$

Explanation :

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. That means, the loss of electrons takes place.

Or we can say that, oxidation reaction occurs when a reactant losses electrons in the reaction.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. That means, the gain of electrons takes place.

Or we can say that, reduction reaction occurs when a reactant gains electrons in the reaction.

According to the electrochemical series, $Zn^{2+}$ most likely to be reduced because

Hence, the ion most likely to be reduced is $Zn^{2+}$ .

3 0

3 years ago

Sodium has______ Valence electrons and bismuth has ________ electrons

Triss [41]

Answer:

Sodium has 1 valence electron and bismuth has 83 electrons (5 valence electrons)

Explanation:

5 0

3 years ago

A student prepares a aqueous solution of butanoic acid . Calculate the fraction of butanoic acid that is in the dissociated form

ella [17]

Answer:

15.4%

Explanation:

If Ka = 0.54 mM = 1.51x10⁻⁵

Then;

C₄H₈O₂ --------> C₄H₇O₂⁻ + H⁺

I 0.54x10⁻³ 0 0

E 0.54x10⁻³(1-x) 0.54x10⁻³x 0.54x10⁻³x

Recall that x is the percentage degree of dissociation

From the ICE table;

Ka = [C₄H₇O₂⁻] [ H⁺]/[C₄H₈O₂]

1.51x10⁻⁵=(0.54x10⁻³x) (0.54x10⁻³x)/ 0.54x10⁻³(1-x)

1.51x10⁻⁵ = 0.54x10⁻³x^2/1-x

1.51x10⁻⁵(1-x) = 0.54x10⁻³x^2

1.51x10⁻⁵ - 1.51x10⁻⁵x = 0.54x10⁻³x^2

Hence;

0.54x10⁻³x^2 + 1.51x10⁻⁵x - 1.51x10⁻⁵=0

x^2 + 0.028x - 0.028 = 0

Solving the quadratic equation here;

x = 0.154 or −0.182

Ignoring the negative result, x = 0.154

Hence, fraction of butanoic acid that is in the dissociated form in this solution = 15.4%

3 0

3 years ago

A chemist has one solu6on that is 40% sulfuric acid and one that is 10% sulfuric acid. How much of each should she use to make 2

kipiarov [429]

Answer:

12 L of 40% sulfuric acid solution and 8 L of 10% sulfuric acid solution are needed to make 20 L of sulfuric acid solution.

Explanation:

For first solution of sulfuric acid :

C₁ = 40% , V₁ = ?

For second solution of sulfuric acid :

C₂ = 10% , V₂ = ?

For the resultant solution of sulfuric acid:

C₃ = 28% , V₃ = 20L

Also,

V₁ + V₂ = V₃ = 20L ......................................(1)

Using

C₁V₁ + C₂V₂ = C₃V₃

40×V₁ + 10×V₂ = 28×20

So,

40V₁ + 10V₂ = 560........................................(2)

Solving 1 and 2 as:

V₂ = 20 - V₁

Applying in 2

40V₁ + 10(20 - V₁) = 560

40V₁ + 200 - 10V₁ = 560

30V₁ = 360

V₁ = 12 L

So,

V₂ = 20 - V₁ = 8L

12 L of 40% sulfuric acid solution and 8 L of 10% sulfuric acid solution are needed to make 20 L of sulfuric acid solution.

4 0

4 years ago