I believe the answer is C
Answer:
Water
Explanation :-
Higher the intermolecular forces between the liquid particles, higher its boiling point.
One type of chemical process that can be either exothermic or endothermic is dissolving of salts in water. A salt is a compound made up of positively charged ions and negatively charged ions which are held together in a solid state because the positive and negative charges attract one another.
Answer:
24 atoms of H or 1.4 x 10²⁵ hydrogen atoms
Explanation:
simple method
1 H₂O has atoms of hydrogen and 1 atom of oxygen
while 12H₂O will have 24 atoms of hydrogen and 12 atom of oxygen
by Avagadros number
molar mass of water H₂0=18.01528 g/mol
1 mole of H₂0 have 2 moles of Hydrogen
one mole of water= 6.02⋅10²³water molecules =1.2 x 10²⁴hydrogen atoms
12 mole of H₂O = 1.2 x 10²⁴ x 12= 1.4 x 10²⁵ hydrogen atoms
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1.4 x 10²⁵ hydrogen atoms in 12 moles of H₂O
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a) The reaction is exothermic since the overall enthalpy change is negative. this means that the system has lost energy to the environment, namely, the apparatus and due to drought.
b) We first calculate the number of moles in 3.55 grams of magnesium.
number of moles= mass/ atomic mass
=3.55/24
=0.1479 moles(to 4sf)
now, if 2 moles of magnesium give -1204kJ
How much energy is given by 0.1479 moles
= (0.1479×-1204kJ)
=-89.0358kJ (don't forget the negative sign)
c) two molesof MgO produces -1204kJ of energy
then -234kJ will be produced by
=(-234kJ×2moles)/1204kJ
=0.3887moles
one mole of MgO weighs 24+16=40
therefore the mass produced is 0.3887moles×40=15.548grams
(d) we first find the number of moles of MgO in 40.3 grams
number of moles=mass/RFM
=40.3g/40= 1.0075moles
if 2 moles of MgO give 1204 kJ then decomposing 1.0075 moles requires
(1.0075 moles×1204kJ)/2=606.515kJ
