Chemical change happens when a substance combines with
another substance to form a new substance. It produces chemical reactions and
generally is not reversible except by further chemical reactions. Heat is sometimes
produced in some reactions. When chemical reactions occur, the atoms are
rearranged and an energy change happens along with it as new products are
generations. At a molecular level, chemical changes involves the making or
breaking of bonds between atoms. Some examples of chemical change are iron
rusting (iron oxide forms) and bread rising (yeast converts carbohydrates into
carbon dioxide gas).
<u>We are given:</u>
Mass of ice = 21 grams
The ice is already at 0°c, the temperature at which it melts to form water
Molar heat of fusion of Ice = 6.02 kJ/mol
<u>Finding the energy required:</u>
<u>Number of moles of Ice: </u>
Molar mass of water = 18 g/mol
Number of moles = given mass/ molar mass
Number of moles = 21 / 18 = 7/6 moles
<u>Energy required to melt the given amount of ice:</u>
Energy = number of moles * molar heat of fusion
Energy = (7/6) * (6.02)
Energy = 7.02 kJ OR 7020 joules
A technician mixes 80 ml of a 5% solution with 10 ml of water. the final percentage strength of the solution prepared is 40 %.
given that :
8 ml of a 5 % solution mix with 10 ml . that means the 80 mL of 5 % solution is diluted with water of 10 mL
therefore, 80 × 5 = 10 × x %
x % = 40 %
Therefore, the final percentage strength of the solution is 40 %
Thus, A technician mixes 80 ml of a 5% solution with 10 ml of water. the final percentage strength of the solution prepared is 40 %.
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Answer:
no examination in 16.9g in molicube i n gas
Explanation:
sana po makatulong po sa inyo
