Problem One
You will use both m * c * deltaT and H = m * heat of fusion.
Givens
m = 12.4 grams
c = 0.1291
t1 = 26oC
t2 = 1204
heat of fusion (H_f) = 63.5 J/grams.
Equation
H = m * c * deltaT + m * H_f
Solution
H = 12.4 * 0.1291 * (1063 - 26) + 12.4 * 63.5
H = 1660.1 + 787.4
H = 2447.5 or 2447.47 is the exact answer. I have to leave the rounding to you. I have no idea where to round it although I suspect 2450 would be right for 3 sig digs.
Problem Two
Formula and Givens
t1 = 14.5
t2 = 50.0
E = 5680
c = 4.186
m = ??
E = m c * deltaT
Solution
5680 = m * 4.186 * (50 - 14.5)
5680 = m * 4.186 * (35.5)
5680 = m * 148.603 * m
m = 5680 / 148.603
m = 38.22 grams That isn't very much. Be very sure you are working in joules. You'd leave that many grams in the kettle after drying it thoroughly.
m = 38.2 to 3 sig digs.
Answer:
2nd one In my opinion....
Answer:
Y, Q, W, Z and X
Y > Q > W > Z > X
Explanation:
To know the most reactive element, the element will be able to displace other metal in it compound. We also have to observe if the reaction occur. If the reaction didn't occur, that means the element is not reactive than the metal found in the other reactant. Invariably their will be no displacement.
Q + w+ Reaction occurs
Q element displace the metal w in it compound . This means Q is more reactive.
x +z+ No reaction
No reaction here. This means x is less reactive than z as it couldn't displace z in it compound.
w + z+ Reaction occurs
w is more reactive than z as it displaces z in it compound.
Q+ + Y Reaction occurs
Y is more reactive than Q as it displaces Q in it compounds.
Therefore, the most reactive to the least reactive is arrange as follows.
Y, Q, W, Z and X
Answer:
These two numbers are fixed for an element. The mass number tells us the number the sum of nucleons of protons and neutrons in the nucleus of an atom. The atomic number also known as the proton number is the number of protons found in the nucleus of an atom. ... The atomic number uniquely identifies a chemical element.
Explanation:
