When ice melts, the physicals state changes from solid to liquid. The energy or the heat required (q) required to change a unit mass (m) of a substance from solid to liquid is known as the enthalpy or heat of fusion (ΔHf). The variables; q, m and ΔHf are related as:
q = m * ΔHf
the mass of ice m = 65 g
the heat of fusion of water at 0C = ΔHf = 334 J/g
Therefore: q = 65 g * 334 J/g = 21710 J
Now:
4.184 J = 1 cal
which implies that: 21710 J = 1 cal * 21710 J/4.184 J = 5188.8 cal
Hence the heat required is 5188.8 cal or 5.2 Kcal (approx)
Answer:
according to my reading
use own words
Explanation:
Salts are combinations of acids and bases. The cation comes from a base and the anion from an acid. Therefore, to make KNO3 we react KOH and HNO3. See how that is done? We write K and add OH to make KOH. We take NO3 and add H to make HNO3.
Answer:
The correct answer is - <u>alternating</u> and <u>direct</u>, in order.
Explanation:
Alternating current is is type of electric current that is characterized by the direction of the flow of electrons in continuously switches its directs in opposite manner at regular cycles. While direct current or DC is flow of the electrons that move from starting to end in one direction.
Spinning turbines always leads to the alternating electric current while only solar energy produces the direct current with the help of the solar panels.
Thus, the correct answer is - <u>alternating</u> and <u>direct</u>, in order.
I would say C is the most correct.
In D it depends on what water source you're using. Let's say it is a waterfall, then the source of the water (melting ice or a lake) may disappear in the future.
If you're using underwater "windmills" placed in the ocean, then you would expect it to last a while as the ocean will not disappear in the near future.
