Metric dimensional analysis worksheet problem: 645 kg to g

Which electron transition represents a gain of energy?

xz_007 [3.2K]

The correct answer is (A) from 2nd to 3rd shell.

The explanation :

when a gain of energy is the shift of the electrons from a shell of low energy to the shell of high energy

and we have here 2nd shell is the shell of low energy, and 3rd shell is the shell of high energy.

∴ (A) from 2nd to 3rd shell is the correct answer.

5 0

3 years ago

Osmotic pressure Π is given by the relation:Π = iMRTwhere i is the van’t Hoff factor, M is the concentration of solute, R is the

lions [1.4K]

Answer: The concentration of solute is 0.503 mol/L

Explanation:

To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

$\pi=icRT$

where,

$\pi$ = osmotic pressure of the solution = 24 atm

i = Van't hoff factor = 2 (for NaCl)

c = concentration of solute = ?

R = Gas constant = $0.08\text{ L atm }mol^{-1}K^{-1}$

T = temperature of the solution = $25^oC=[273+25]=298K$

Putting values in above equation, we get:

$24atm=2\times c\times 0.08\text{ L.atm }mol^{-1}K^{-1}\times 298K\\\\c=0.503mol/L$

Hence, the concentration of solute is 0.503 mol/L

5 0

3 years ago

A person tries to heat up her bath water by adding 5.0 l of water at 80c to 60 l of water at 30c. what is the final temperature

Sophie [7]

We can calculate the final temperature from this formula :

when Tf = (V1* T1) +(V2* T2) / (V1+ V2)

when V1 is the first volume of water = 5 L

and V2 is the second volume of water = 60 L

and T1 is the first temperature of water in Kelvin = 80 °C +273 = 353 K

and T2 is the second temperature of water in Kelvin = 30°C + 273= 303 K

and Tf is the final temperature of water in Kelvin

so, by substitution:

Tf = (5 L * 353 K ) + ( 60 L * 303 K) / ( 5 L + 60 L)

= 1765 + 18180 / 65 L

= 306 K
= 306 -273 = 33° C

8 0

3 years ago

How much energy (heat) is required to convert 248 g of water from 0 oC to 154 oC? Assume that the water begins as a liquid, that

Nuetrik [128]

Answer:

The total heat required is 691,026.36 J

Explanation:

Latent heat is the amount of heat that a body receives or gives to produce a phase change. It is calculated as: Q = m. L

Where Q: amount of heat, m: mass and L: latent heat

On the other hand, sensible heat is the amount of heat that a body can receive or give up due to a change in temperature. Its calculation is through the expression:

Q = c * m * ΔT

where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the change in temperature (Tfinal - Tinitial).

In this case, the total heat required is calculated as:

Q for liquid water. This is, raise 248 g of liquid water from O to 100 Celsius. So you calculate the sensible heat of water from temperature 0 °C to 100° C

Q= c*m*ΔT

$Q=4.184\frac{J}{g*C} *248 g* (100 -0 )C$

Q=103,763.2 J

Q for phase change from liquid to steam. For this, you calculate the latent heat with the heat of vaporization being 40 and being 248 g = 13.78 moles (the molar mass of water being 18 g / mol, then $\frac{248 g}{18 \frac{g}{mol} } =13.78 moles$ )