1) Chemical reactions produce new substances
Ans (d)
2) The symbol, Δ in a chemical reaction means that heat of supplied to the reaction.
Ans (a)
3) A skeleton equations does not show the reaction stoichiometry, i.e. the relative amounts of reactants and products.
Ans (d)
The mass of melted gold to release the energy would be 3, 688. 8 Kg
<h3>How to determine the mass</h3>
We have quantity of energy is;
Q = n × HF
n = number of moles
HF = heat of fusion
Let's find number of moles
235.0 = n × 12.550
number of moles = 
= 18. 725 moles
Note that molar mass of Gold is 197g/ mol
Number of moles = mass/ molar mass
Mass = number of moles × molar mass
Mass = 18. 725 × 197
Mass = 3, 688. 8 Kg
Thus, the mass of melted gold to release the energy would be 3, 688. 8 Kg
Learn more about molar heat of fusion here:
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Answer:
The answer to your question is 3 L of solution 40% and 2 L of solution 20%
Explanation:
Data
Final volume = Vf = 5000 ml = 5 L
Final concentration = Cf = 32%
Concentration 1 = C1 = 40%
Concentration 2 = C2 = 20%
Volume 1 = x
Volume 2 = 5 - x
Process
1.- Write an equation to solve this problem
VfCf = C1V1 + C2V2
2.- Substitution
32(5) = 40x + 20(5 - x)
3.- Solve for x
160 = 40x + 100 - 20x
160 - 100 = 40x - 20x
60 = 20x
60/20 = x
x = 3
Then, Volume 1 = 3 L
4.- Find Volume 2
Volume 2 = 5 - 3
Volume 2 = 2 L
Answer:
science needs both ideas the hypothesis and facts the quantitative results to move forward
Explanation:
the two primary features of a scientific hypothesis are falsifiability and testability which are reflected in an If…then statement summarizing the idea and in the ability to be supported or refuted through observation and experimentation
