What is the meaning of Pangaea


Answer 1
Answer: It was the first continent, which later divided into 2, then more and more pieces, until we've got the continents of today.
Panthalassa was the ocean surrounding it those days.
Answer 2
Answer: It was actually what they named the one piece of continent that today is broken into 7 continents

Related Questions

What values do we plot on the yaxis of a graph?A. The dependent variableB. The independent variableC. The linear valuesD. The inverse values
A new candy company wants to determine what color they should make their new chocolate candies to maximize sales. They perform a controlled study at a number of shopping malls, offering bright purple, royal blue, and lime green colored candies. They ask the participants to rate their favorite. Candy color is the A) control variable. B) dependent variable. C) independent variable. D) qualitative variable.
Which is a difference between global and local winds?
Gold melts at 1064 c. Melting point is a ___.A)chemical change B)chemical propertyC)physical change D)physical property
What property of a solution is the same before and after it is diluted?A. amount of soluteB. total volumeC. amount of solventD. concentration

In a longitudinal wave the motion of a disturbance is _____ to the wave motionA.parallel
D. in the same direction


Answer: The correct answer is Option A.


Waves are characterized into two types:

  1. Transverse wave: These waves are the waves where, particles of the medium travel perpendicularly to the direction of the wave. These waves do not require any medium to travel and can travel in vacuum also. For Example: Light waves.
  2. Longitudinal waves: These waves are the waves, where particles of the medium move in the direction of the wave which means that the particles move parallel to the direction of the wave. These waves requires a medium to travel. For Example: Sound Waves.

Hence, the correct answer is Option A.

It is parallel. The direction of energy transfer is parallel to oscillation of particles in the medium. 

What is a safety precaution that should be taken when investigating the electrolysis of lead bromide?


You should wear eye Protection

Wear Gloves and wash hands after the investigation.

Lead bromide is toxic and dangerous for the environment.

Bromine is corrosive, toxic and very dangerous for the environment.

A mixture of He, Ne, and N2 gases are a pressure of 1.348. If the pressures of He and Ne are 0.124 atm, what is the partial pressure of N2 in the mixture ?


Answer :  The partial pressure of N_2 in the mixture is, 1.224 atm

Solution :

According to the Dalton's law, the total pressure of the gas is equal to the sum of the partial pressure of the mixture of gasses.



P_T = total partial pressure of He,Ne\text{ and }N_2 = 1.348 atm

P_(He) = partial pressure of helium

P_(Ne) = partial pressure of neon

P_(N_2) = partial pressure of nitrogen

As we are given that,


Now put all the given values in above expression, we get the partial pressure of the nitrogen gas in the mixture.



Therefore, the partial pressure of N_2 in the mixture is, 66 Kpa

The Best Answer: 1 - (.47+.23) = 0.30

If Ne has a mole fraction of 0.47 (or 47/100) and Ar is 0.23, then H2(or He) has a mole fraction of 0.30

This means the gas mixture is 30/100 H2(or He).

7.85 x 0.30 = 2.355 atm

How many atoms of hydrogen are in 24.4 g of methane?



The number of atom is 3.67*10^24 atoms


Molar mass of methane CH4 is 16.0g/mol

Using this to divide the mass

24.4g/16.0 = 1.525mol

1 mol CH4 contains 1 mol of Carbon C and 4 mol of hydrogen H, so 1.525mol contains 4(1.525)=6.1 molH

Using avogadro number : (6.1mol)(6.02*10^23)

= 3.67*10^24 atoms

Final answer:

There are 3.66 × 10^24 hydrogen atoms in 24.4 g of methane (CH4). This is calculated by first finding the number of moles of CH4 and then using Avogadro's number to determine the total number of molecules, which is finally multiplied by 4 (the number of hydrogen atoms per CH4 molecule).


The question asks how many atoms of hydrogen are in 24.4 g of methane (CH4). Methane has a molecular formula of CH4, indicating that each molecule contains 4 hydrogen atoms. The molar mass of methane is 16.04 g/mol (12.01 g for carbon + 4 × 1.008 g for hydrogen).

First, calculate the number of moles of methane:

24.4 g CH4 × (1 mol CH4 / 16.04 g CH4) = 1.52 mol CH4

Then, multiply by Avogadro's number to find the total number of methane molecules:

1.52 mol CH4 × (6.022 × 1023 molecules/mol) = 9.15 × 1023 molecules of CH4

Since each molecule of methane has 4 hydrogen atoms, we get:

9.15 × 1023 molecules CH4 × (4 H atoms/molecule) = 3.66 × 1024 hydrogen atoms.

8. Select the lattice energy for rubidium chloride from the following data (in kJ/mol]Rb(s) ---> Rb(g) = 85.8
IE1(Rb) = 397.5
BE(Cl2) = 226
deltaHf(RbCl) = -431
Electron Affinity Cl = -332

a. -53.7
b. +53.7
C. -695
d. -808
e. +808​



Option C


The chemical reactions which are involved while solving this problem is there in the file attached and each chemical reaction is represented by a certain equation number

Lattice energy for rubidium chloride ( RbCl) is represented by the equation 6

Equation 1 represents the change in enthalpy for formation of RbCl

Equation 2 represents the sublimation reaction of rubidium

Equation 3 represents the ionization enthalpy of rubidium

Equation 4 represents the enthalpy of atomization of chlorine which means it describes the bond enthalpy of Cl2 molecule

Equation 5 represents the electron affinity of chlorine

To find the lattice energy for RbCl we have to use all the equations from 1 to 5 so that at last we get the equation 6

We have to perform operations such as

Equation 1 - equation 2 - equation 3 - equation 4 - equation 5

By performing these operations the intermediate compounds gets cancelled and at last we get equation 6

So Equation 1 ≡  ΔH_(f) = -431 kJ/mol

Equation 2 ≡ Rb(s) ---> Rb(g) = 85.8  kJ/mol

Equation 3 ≡ IE1(Rb) = 397.5  kJ/mol

Equation 4 ≡ BE(Cl2) = 226  kJ/mol

Equation 5 ≡ Electron Affinity Cl = -332  kJ/mol

Value corresponding to the equation 6 will be the value of lattice energy of RbCl and the value is -695·3 kJ/mol

∴ Lattice energy for rubidium chloride is approximately -695 kJ/mol

Final answer:

The lattice energy for rubidium chloride (RbCl) is calculated by substituting the given values into the equation derived from Hess's Law. The calculated lattice energy is found to be -695 kJ/mol.


In this question, you are asked to select the lattice energy for rubidium chloride (RbCl). The lattice energy can be calculated using various given energies including enthalpy of formation (ΔHf), electron affinity (Cl), enthalpy of sublimation, ionization energy, and bond dissociation energy. Using Hess's Law, this can be summed up as:

ΔHf(RbCl) = [Sublimation Energy (Rb) + Ionization Energy (Rb) + 0.5 × Bond Energy (Cl₂) + Electron Affinity (Cl)] - Lattice Energy (RbCl)

By rearranging this formula, we find that the Lattice Energy (RbCl) = [Sublimation Energy (Rb) + Ionization Energy (Rb) + 0.5 × Bond Energy (Cl₂) + Electron Affinity (Cl)] - ΔHf(RbCl). Substituting in the given values, we find the lattice energy to be -695 kJ/mol. Therefore, the correct option is C. -695.

Learn more about Lattice Energy here:



Which of the following is not a characteristic of a theme A. it runs throughout a piece
B. it. is stated clearly
C. it has universal quality
D. it is present in music, literature, visual art, and other forms of artistic expression ​


b it is stated clearly