Although birds' eggs appear to be fragile, they are in fact extremely robust. The oval shape applies the same rules of engineering as an arched bridge; the convex surface can withstand considerable pressure without breaking.

6 0

3 years ago

How to Calculate the de Broglie wavelength for each of the following ? a. an electron with a velocity 10.% of the speed of light

qaws [65]

H = planks constant
m = mass of the object 
u = velocity of the object 

h = 6.626 * 10^-34 J/s 
the mass of an electron is 9.12*10^-31 kg 
10% speed of light = 10% * 3*10^8 = 3*10^7 m/s, i dont have my graphing calc with me right now so i leave the technicalities up to you

8 0

3 years ago

How is it that when a salt sample dissolves in water, the delta S for the process is positive?

Bess [88]

Answer:-

Water is highly ordered. In water each oxygen atom is connected to others around it through hydrogen bonding via bridging hydrogen atoms. When a salt like NaCl is dissolved, some of these Hydrogen bonds break.

When a salt like NaCl dissolves in water, the NaCl breaks in to ions Na+ and Cl-.

The water molecules now surround these ions.

The slightly negative oxygen end of water molecule gets near the Na+, while the slightly positive Hydrogen of water molecule gets near the Cl-.

So before salt sample dissolve, the water molecules were highly ordered due to hydrogen bonding. Now after salt dissolve there is a decrease in order and thus an increase in disorder of the water molecules.

Due to increase in disorder, entropy which is a measure of disorder increases. Since entropy increases, delta S for the process is positive.

4 0

3 years ago