Answer:
Explanation:
Ionic (or electrovalent) compounds conduct electricity when there they are in the aqueous state/solution because the charges of ions of these compounds are what carry the electric charges in the aqueous solution as a result of free movement within the aqueous solution which they do not "have" when in there solid state (where they have a highly restricted movement/compacted structure).
The correct answer is a. This is because the pH of a solution is defined as -log10(concentration of H+ ions). An inverse logarithmic scale such as this means that a solution with a lower concentration of H+ ions will have a higher pH than one with a higher concentration. Therefore we know that the pH of the second sample will be higher than the first.
Since the logarithmic scale has the base 10, a change by 1 on the scale is a consequence of multiplication/division of the H+ concentration by a factor of 10. As the scale is inverse, this means that a decrease of concentration by factor 1000 is equivalent to increasing the pH by (1000/10) = 3.
Answer:
Specific heat of alloy = 0.2 j/ g.°C
Explanation:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
Given data:
Mass of bold = 25 g
Heat absorbed = 250 J
Initial Temperature = 25°C
Final temperature = 78°C
Specific heat of alloy = ?
Solution:
Change in temperature:
ΔT = 78°C - 25°C
ΔT = 53°C
Now we will put the values in formula.
Q = m.c. ΔT
250 j = 25 g × c ×53°C
250 j = 1325 g.°C × c
250 j / 1325 g.°C = c
c = 0.2 j/ g.°C
No! That’s why they’re called theories. Most of them have a lot of facts to back it up however the theories themselves are either proven or just hypothetical.
We write DE = q+w, where DE is the internal energy change and q and w are heat and work, respectively.
(b)Under what conditions will the quantities q and w be negative numbers?
q is negative when heat flows from the system to the surroundings, and w is negative when the system does work on the surroundings.
As an aside: In applying the first law, do we need to measure the internal energy of a system? Explain.
The absolute internal energy of a system cannot be measured, at least in any practical sense. The internal energy encompasses the kinetic energy of all moving particles in the system, including subatomic particles, as well as the electrostatic potential energies between all these particles. We can measure the change in internal energy (DE) as the result of a chemical or physical change, but we cannot determine the absolute internal energy of either the initial or the final state. The first law allows us to calculate the change in internal energy during a transformation by calculating the heat and work exchanged between the system and its surroundings.
