Chem Question! (1 Viewer)

[ratcher0071]

Why is water unable to dissolve?

 

[Timothy.Siu]

dissolve wat?

 

[ratcher0071]

dissolve wat?

why can't water dissolve in anything.

 

[bored of sc]

why can't water dissolve in anything.

Water has very strong hydrogen bonds (intermolecular forces) due the large difference in electronegavities of hydrogen (2.2) and oxygen (3.5). This means it would be unfavourable for water to break it's intermolecular forces and form intermolecular forces with another substances as the strength of these forces would be smaller than that of the hydrogen bonds (note: hydrogen bonds are intermolecular forces NOT BONDS) already present in the molecule.

Can someone please verify my information I have presented above?

 

[ratcher0071]

Another question:

How do you account for mass change in a chemical reaction?

 

[Continuum]

Uhh... it doesn't really explain what he's asking.

Back to the OP, water can dissolve. Dissolving just basically means forming a solution - a solute being surrounded by many solvent particles. So what you are really asking when you question 'whether water can dissolve' is whether or not it can play the role of the solute, which it can.

For example, when you have a little bit of water and put it into a bucket full of ethanol, you wouldn't say that the ethanol dissolved into the water would you? You would say that the water dissolved in the ethanol.

 

[Finx]

Another question:

How do you account for mass change in a chemical reaction?

What are you given in the question?

Usually you'd equate everything back to moles, then use n=m/mm to find the mass.

 

[bubblesss]

Another question:

How do you account for mass change in a chemical reaction?[/quot


according to the law of conservation of mass, the mass of the reactants is slightly greater than the mass of the products. the slight mass is lost as energy during the chemical reaction either as heat light or sound energy.

 

[ratcher0071]

Another question:

How do you account for mass change in a chemical reaction?[/quot


according to the law of conservation of mass, the mass of the reactants is slightly greater than the mass of the products. the slight mass is lost as energy during the chemical reaction either as heat light or sound energy.

Are you sure? Because mass and energy are two different things.

 

[ratcher0071]

What are you given in the question?

Usually you'd equate everything back to moles, then use n=m/mm to find the mass.

Say in general, if the mass of the reactants are higher than the mass of the products, what happens to this "lost" mass?

 

[bubblesss]

Are you sure? Because mass and energy are two different things.

yep i'm sure. the slight weight loss is due to the fact that some of the substance was lost as energy.

for eg: when magnesium burns it loses a bit of its mass. that is due to the fact that the mass burns and is lost as heat and light energy.

sum1 correct me if i'm wrong!!!

 

[tommykins]

Are you sure? Because mass and energy are two different things.

No they're not.

e = mc², mass is simply condensed energy.

according to the law of conservation of mass, the mass of the reactants is slightly greater than the mass of the products. the slight mass is lost as energy during the chemical reaction either as heat light or sound energy.

You could have worded it better, but you have the general idea.

It is the Law of Conservation of Energy, we know from E = mc² that mass IS energy. During a chemical reaction (mainly a natural transmutation ie Uranium 236), bonds are broken and the mass of the particles in the reactants are greater than the mass of the particles in the products. In order to adhere to this mass defect, the "missing" mass is due to the release of energy in one form or another.

If you do physics in year 12 and are doing the Quanta to Quarks option, you'll learn about this.

 

[bubblesss]

Say in general, if the mass of the reactants are higher than the mass of the products, what happens to this "lost" mass?

lost mass is lost as sound, light, chemical or sound energy.

 

[ratcher0071]

I would like to thank you all for contributing.

 

[bubblesss]

No they're not.

e = mc², mass is simply condensed energy.

You could have worded it better, but you have the general idea.

It is the Law of Conservation of Energy, we know from E = mc² that mass IS energy. During a chemical reaction (mainly a natural transmutation ie Uranium 236), bonds are broken and the mass of the particles in the reactants are greater than the mass of the particles in the products. In order to adhere to this mass defect, the "missing" mass is due to the release of energy in one form or another.

If you do physics in year 12 and are doing the Quanta to Quarks option, you'll learn about this.

sorry if i'm wrong- my bad
but if im not mistaken im sure i've heard of two different laws
the law of conservation of energy/mass???????

 

[ratcher0071]

Law of conservation of Energy:

Energy cannot be created or destroyed, only be transformed into other forms (heat, light, sound, kinetic, potential, etc...)

Law of conservation of mass:

Matter cannot be created or destroyed, only rearranged.

 

[ahhliss]

Conservation of mass: Matter cannot be created or destroyed, but atoms and stuff can be rearranged.
Conservation of energy: Energy cannot be created or destroyed, but it can be transformed into another type of energy.

Is that it? I don't really remember :S

 

[ratcher0071]

Conservation of mass: Matter cannot be created or destroyed, but atoms and stuff can be rearranged.
Conservation of energy: Energy cannot be created or destroyed, but it can be transformed into another type of energy.

Is that it? I don't really remember :S

yeah it is. :uhhuh:

 

[tommykins]

No they're not.

e = mc², mass is simply condensed energy.




sorry if i'm wrong- my bad
but if im not mistaken im sure i've heard of two different laws
the law of conservation of energy/mass???????

Technically you're right in both respects