Electron microscopes differ from light microscopes in that they produce an image of a specimen by using a beam of electrons rather than a beam of light. Electrons have much a shorter wavelength than visible light, and this allows electron microscopes to produce higher-resolution images than standard light microscopes
Answer:
How much heat energy required to convert following?
How much heat energy, in kilojoules, is required to convert 47.0 g of ice at -18.0 C to water at 25.0 C ?
Specific Heat of Ice - 2.09 j/g * c
This is how I did it and the answer is wrong...Please check and correct me
Q = m * Cice * Change in Temp
Q = (47.0 g)(2.09 J/g*c)(43) = 4222.6 J * 0.001 kj / j = 4.22 kj
<span>293 grams
The formula for the wavelength of a massive particle is
λ = h/p
where
λ = wavelength
h = Plank constant (6.626070040Ă—10^â’34 J*s)
p = momentum (mass times velocity)
So let's solve for momentum and from there get the mass
λ = h/p
λp = h
p = h/λ
Substitute known values and solve
p = 6.626070040Ă—10^â’34 J*s/3.45Ă—10^-34 m
p = 1.92 J*s/m
Since momentum is the product of mass and velocity, we have
p = M * V
p/V = M
So substitute again, and solve.
p/V = M
1.92 J*s/m / 6.55 m/s = M
1.92 kg*m/s / 6.55 m/s = M
1.92 kg*m/s / 6.55 m/s = M
0.293 kg = M
So the mass is 293 grams</span>
Physical change: a change in which no new substances are formed. the form of the substance is changed but not it's chemical composition (ice melting, bread toasting)
chemical change: any change that results in the formation of new chemical substances. this type of change modifies molecules and atoms by making and breaking the bonds between atoms! (iron rusting, gas burning)
so basically a physical change just changes the appearance of a substance, but a chemical change changes the makeup on a molecular level. i hope this helps you out!
4. Isotopes of the same element