All categories

1 year ago

Why was Mendeleev's first Periodic Table not accepted my the scientist community when it was published in the late 1800s?

2 answers:

4 0

He thought the gaps or "periods" in his horizontal rows had not been discovered yet .he never saw this as a problem until he was able to work them out and he ended up being right.

stepan [7]1 year ago

3 0

They found new elements

You might be interested in

According to Valence Shell Electron Pair Repulsion (VSEPR) theory, which statement is correct? If a molecule has four pairs of e

andrew11 [14]

Answer: Option 1

Explanation: hopes it helps

6 0

1 year ago

Given a water solution that contains 1.704 kg of HNO:/kg H:O and has a specific gravity of 1.382 at 20 °C, express the compositi

TEA [102]

Answer:

a) 63,0%

b) 54,4 Pounds HNO₃ per cubic foot of solution

c) 13,8 M

Explanation:

a) Weight percent is the ratio solute:solution times 100:

$\frac{1,704 kg HNO_3}{2,704 kg Solution}$ = 63,0%

b) Pounds HNO₃ per cubic foot of solution at 20 °c

Pounds HNO₃:

1,704 kg $\frac{2,20462 pounds}{1 kg}$ = 3,7567 pounds

Cubic foot:

2,704 kg $\frac{1 L}{1,382 kg}$ x $\frac{1 cubic foot }{28,3168 L}$ = 0,069 ft³

Thus: $\frac{3,7567 pounds}{0,069ft^3} =$ = 54,4 Pounds HNO₃ per cubic foot of solution

c) Moles of HNO₃:

1704 g HNO₃ $\frac{1 mol HNO_3}{63,01 g }$ = 27,04 moles

Liters of solution:

2,704 kg $\frac{1 L}{1,382 kg}$ = 1,96 L of solution

Molarity:

$\frac{27,04 mol}{1,96 L}$ = 13,8 M

4 0

2 years ago

In a favorable reaction, the free energy of the products is ________ the free energy of the reactants. In a favorable reaction,

steposvetlana [31]

Answer:

In a favorable reaction, the free energy of the products is less than the free energy of the reactants.

Explanation:

The free energy of a system is the amount of a system's internal energy that is available to perform work. The different forms of free energy include Gibbs free energy and Helmholtz free energy.

In a system at constant temperature and pressure, the energy that can be converted into work or the amount of usable energy in that system is known as Gibbs free energy. In a system at constant temperature and volume, the energy that can be converted into work is known as Helmholtz free energy.

The change in free energy of a system is the maximum usable energy that is released or absorbed by a system when it goes from the initial state (i.e., all reactants) to the final state (i.e., all products).

In a chemical reaction, some bonds in the reactants are broken by absorbing energy and new bonds are formed in the products by releasing energy. As the reaction proceeds, the free energy of reactants is much greater than the products. As the products are formed, the concentration of reactants decreases and the difference in their free energy also decreases. This chemical reaction will occur until chemical equilibrium is achieved i.e., the free energy of the products and reactants is equal and the difference in their free energy is zero.

5 0

1 year ago

Read 2 more answers

What crossed-aldol product results when butanal is heated in the presence of excess benzaldehyde and sodium hydroxide? draw the

alexdok [17]

Answer:
2-(hydroxy(phenyl)methyl)butanal is formed as cross aldol product.

Explanation:
The mild acidic proton present at alpha position in 1-Butanal is abstracted by strong base NaOH. The enolate formed is the conjugate base of 1-Butanal and cacts as a nucleophile. The enolate is then added across carbonyl group of Benzaldeyde and yield 2-(hydroxy(phenyl)methyl)butanal. The reaction is as follow,

8 0

2 years ago

What does the simplified model of the hall effect give for the density of free electrons in the unknown metal?

evablogger [386]

The simplified model of the hall effect proved that the current (electric) in metals are carried by electrons and not protons. The hall effect introduced the hall coefficient which is the ratio of the induced electric field to the current density x applied magnetic field. This coefficient is unique for each type of metal.

3 0

1 year ago