Answer:
How much heat energy required to convert following?
How much heat energy, in kilojoules, is required to convert 47.0 g of ice at -18.0 C to water at 25.0 C ?
Specific Heat of Ice - 2.09 j/g * c
This is how I did it and the answer is wrong...Please check and correct me
Q = m * Cice * Change in Temp
Q = (47.0 g)(2.09 J/g*c)(43) = 4222.6 J * 0.001 kj / j = 4.22 kj
The answer to this question would be: 3.125%
Half-life is the time needed for a radioactive molecule to decay half of its mass. In this case, the strontium-89 is already gone past 5 half lives. Then, the percentage of the mass left after 5 half-lives should be:
100%*(1/2^5)= 100%/32=3..125%
Answer:
B. chemical
Explanation:
Chemical change cannot go back to its original form
Anions are negative ions so it’s when an atom gains electrons
We are given with a compound, Zinc (Zn) having a 1.7 x 10
^23 atoms. We are tasked to solve for it's corresponding mass in g. We need to
find first the molecular weight of Zinc, that is
Zn= 65.38 g/mol
Not that 1 mol=6.022x10^{23} atoms, hence,
1.7 x 10 ^23 atoms x 1 mol/6.022x10^{23} atoms x65.38
g/ 1mol
=18.456 g of Zn
Therefore, the mass of Zinc 18.456 g
