Dmitri mendeleev contribution to the periodic table.

1 answer:

8 0

In 1871, a Russian Chemist, Dimitri Mendeleev, gave a useful scheme for classification of elements. He presented the first regular periodic table in which elements of similar chemical properties were arranged in eight vertical columns called groups. The horizontal rows of table were called periods. He arranged elements in ascending order of their atomic masses and found that elements having similar chemical properties appeared at regular intervals. This observation was called Periodic Law.

You might be interested in

A pump contains 1.5 L of air at 175 kPa. You draw back on the piston of the pump, expanding the volume until the pressure reads

Tresset [83]

Answer:

$\large \boxed{\text{86.8 L}}$

Explanation:

The temperature and amount of gas are constant, so we can use Boyle’s Law.

$p_{1}V_{1} = p_{2}V_{2}$

Data:

$\begin{array}{rclrcl}p_{1}& =& \text{0.579 atm}\qquad & V_{1} &= & \text{150 L} \\p_{2}& =& \text{1.00 atm}\qquad & V_{2} &= & ?\\\end{array}$

Calculations:

$\begin{array}{rcl}0.579 \times 150 & =& 1.00V_{2}\\86.85 & = & 1.00V_{2}\\V_{2} & = &\dfrac{86.85}{1.00}\\\\& = &\textbf{86.8}\\\end{array}\\\text{The new volume of the gas is } \large \boxed{\textbf{86.8 L}}$

6 0

3 years ago

Why is desertification a problem?

Gnesinka [82]

Because if all the trees and grasslands are to disappear and turn into deserts then there would be no oxygen for us

6 0

2 years ago

Read 2 more answers

If 20 grams of N2 react completely with H2 , how many moles of NH3 are produced? Show Work

Maslowich

This is the balanced eq
N2 + 3H2 -> 2NH3
first you need to find mole of N2 by using
mol = mass ÷ molar mass.
mol N2= 20g ÷ (14.01×2)g/mol
=0.7138mol
then look at the coefficient between H2 and NH3.
it is N2:NH3
1:2
0.7138:0.7138×2
0.7138:1.4276 moles
moles of NH3 = 1.4276 moles

5 0

3 years ago

Can someone help me with this pls

diamong [38]

The chemical elements are arranged in order of increasing atomic number. Answer A.

7 0

2 years ago

Read 2 more answers

Why is a lot of energy needed to break covalent bonds

gulaghasi [49]

Answer:

The strength of a bond between two atoms increases as the number of electron pairs in the bond increases.