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3 years ago

Which scientist was the first to propose the hellocentric model of the universe?

Chemistry

1 answer:

Westkost [7]3 years ago

6 0

Nicolaus Copernicus

Nicolaus Copernicus in his De revolutionibus orbium coelestium ("On the revolution of heavenly spheres", first printed in 1543 in Nuremberg), presented a discussion of a heliocentric model of the universe in much the same way as Ptolemy in the 2nd century had presented his geocentric model in his Almagest.

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If a straight-chain hydrocarbon is a gas at room temperature, how many carbon atoms will it have?

Orlov [11]

The fewer the carbon atoms, the closer it is to being a gas. The only one you have to check out is A which is hexane. You know that gasoline at the pumps has 8 carbons and its a liquid. So B and C are both not gases because they are above 8.

C6 (hexane) is a liquid at room temperature not a gas.

The answer is D. If there is a gas present, it must be C3

6 0

3 years ago

24 POINTS!!!!!!!!!!

Oliga [24]

Your answer is going to be A, because it was shoved harder, it will go faster

8 0

3 years ago

Read 2 more answers

Correct?

erica [24]

Correct answer is C

Na2O + H2O ----> 2 NaOH

:-) ;-)

4 0

3 years ago

12. The vapor pressure of water at 90°C is 0.692 atm. What is the vapor pressure (in atm) of a solution made by dissolving 3.68

luda_lava [24]

Answer : The vapor pressure (in atm) of a solution is, 0.679 atm

Explanation : Given,

Mass of $H_2O$ = 1.00 kg = 1000 g

Moles of $CsF$ = 3.68 mole

Molar mass of $H_2O$ = 18 g/mole

Vapor pressure of water = 0.692 atm

First we have to calculate the moles of $H_2O$ .

$\text{Moles of }H_2O=\frac{\text{Mass of }H_2O}{\text{Molar mass of }H_2O}=\frac{1000g}{18g/mole}=55.55mole$

Now we have to calculate the mole fraction of $H_2O$

$\text{Mole fraction of }H_2O=\frac{\text{Moles of }H_2O}{\text{Moles of }H_2O+\text{Moles of }CsF}=\frac{55.55}{55.55+3.68}=0.938$

Now we have to partial pressure of solution.

According to the Raoult's law,

$P_{Solution}=X_{H_2O}\times P^o_{H_2O}$

where,

$P_{Solution}$ = vapor pressure of solution

$P^o_{H_2O}$ = vapor pressure of water = 0.692 atm

$X_{H_2O}$ = mole fraction of water = 0.938

$P_{Solution}=X_{H_2O}\times P^o_{H_2O}$

$P_{Solution}=0.938\times 0.692atm$

$P_{Solution}=0.649atm$

Therefore, the vapor pressure (in atm) of a solution is, 0.679 atm

5 0

3 years ago

What do atom, molecules, and elements have in common

____ [38]

Answer:

Solids, liquids, gases - all matter - are made up of atoms (or other things, like molecules, that are made from atoms)! ELEMENTS are the kinds of atoms that we can have. Carbon is an element, hydrogen is an element, and so is oxygen. ... Atoms can join together - they form bonds together - to make MOLECULES.

6 0

2 years ago