Answer:
We can use heat = mcΔT to determine the amount of heat, but first we need to determine ΔT. Because the final temperature of the water is 55°C and the initial temperature is 20.0°C, ΔT is as follows:
ΔT = Tfinal − Tinitial = 55.0°C − 20.0°C = 35.0°C
given the specific heat of water as 1 cal/g·°C. Substitute the known values into heat = mcΔT and solve for amount of heat:
= heat=(75.0 g)(1 cal/ g· °C )(35.0°C) =
= 75x1x35=2625 cal
Answer: 0.100 m 
Explanation:
Elevation in boiling point is given by:
= Elevation in boiling point
i= vant hoff factor
= boiling point constant
m= molality
1. For 0.100 m 
, i= 3 as it is a electrolyte and dissociate to give 3 ions. and concentration of ions will be 
2. For 0.100 m 
, i= 2 as it is a electrolyte and dissociate to give 2 ions, concentration of ions will be 
3. For 0.200 m 
, i= 1 as it is a non electrolyte and does not dissociate, concentration of ions will be 
4. For 0.060 m 
, i= 4 as it is a electrolyte and dissociate to give 4 ions. and concentration of ions will be 
Thus as concentration of solute is highest for , the elevation in boiling point is highest and thus has the highest boiling point.
Actually Rb or Rubidium in zero state has the following
electron configuration:
<span>1s22s2</span><span>2p6</span><span>3s2</span><span>3p63d10</span><span>4s2</span><span>4p65s1</span>
However we can see that the ion has a 1 positive charge,
which means that it lacks 1 electron, therefore the answer from the choices is:
<span>d.
rb+: 1s22s22p63s23p64s23d104p6</span>
Positive
And Negative for oxygen.
Option no. 2 subtracting the atomic number from the mass number
Example: Zn - 65 atomic weight or mass/mass number
30 atomic number
65-30 = 35 number of neutrons
