Answer:
The correct answer is option C, that is, ΔS and ΔSsurr for the process H2O (s) ⇒ H2O(l) are equal in magnitude and opposite in sign.
Explanation:
The temperature at which solid state of water get transformed into liquid state is termed as the melting point of 0 °C. It can be shown by the reaction:
H2O (s) ⇒ H2O (l)
The degree of randomness of a molecule is known as entropy. With the transformation of ice into liquid state, there is an increase in randomness. Thus, the value of entropy becomes positive as shown:
Entropy change (ΔSsys) = ΔSproduct - ΔSreactant
= (69.9 - 47.89) J mol/K
= 22.0 J mol/K
Therefore, the value of entropy change is positive.
Now the value of entropy for surrounding ΔSsurr will be,
ΔSsurr = -ΔHfusion/T
= -6012 j/mol/273
= -22.0 J/molK
Hence, the value of ΔSsurr and ΔSsys exhibit same magnitude with opposite sign.
Answer:
Explanation:
The relation between new scale and absolute temperature scale is given as follows
Aw = 2 K
for K = 273.15 ( freezing point of water at absolute scale )
Aw = 2 x 273.15 = 546.3 K
So each division of new scale is half the each division of absolute scale
each division of new scale is small .
The value of R = 8.314 J per mole per K
Here per K is equivalent to 2Aw
So the vale of R in new scale = 8.314/2 J per mole per Aw
= 4.157 J per mole per Aw
k = R / N
= 4.157 / 6.02 x 10²³
= .69 x 10⁻²³
= 6.9 x 10⁻²⁴ J per molecule per Aw .
Answer:
Explanation:
The half-life of K-40 (1.3 billion years) is the time it takes for half of it to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table as follows:
No. of Fraction
<u>half-lives</u> <u> t/yr </u> <u>Remaining</u>
0 0 1
1 1.3 billion ½
2 2.6 ¼
3 3.9 ⅛
We see that after 2 half-lives, ¼ of the original mass remains.
Conversely, if two half-lives have passed, the original mass must have been four times the mass we have now.
Original mass = 4 × 2.10 g =
Answer:
Independent Variable: Grade Level
Dependent Variable: Growth in height
Hypothesis: Students in [Insert the grade level you believe will grow the quickest here] will experience the quickest growth in height.
Explanation:
Independent variables are the factors in which you manipulate to gain your results, in this case you would be changing the grade level you would observe to see the height.
Dependent variables are the factors that respond to changes in the independent variables. You don't control these events, you simply observe them. In this case, you merely observe the growth in height in accordance to the different grade levels you observe.
For the hypothesis, you would create your own hypothesis based on a guess you have. You create a hypothesis not based on the data, but on what you believe will be correct before doing the experiment. It doesn't have to be the correct answer, but just your thoughts.
The ionic equation is as below
Ca^2+(aq) + SO4^2-(aq) ---> CaSO4(s)
EXPLANATION
K2SO4(aq) +Cai2(aq) ---> CaSO4(s) + Ki (aq)
ionic equation
= 2K^+(aq) + SO4^2-(aq) + Ca^2+(aq) + 2i^-(aq) --->CaSO4(s) + 2K^+(aq) +2 i^-(aq)
cancel the spectator ions that is 2k^+ and 2i^-
The net ionic equation is therefore
= Ca^2+(aq) + SO4^2-(aq) ----> CaSO4(s)
