A 5.0-gram sample of zinc and a 50.-milliliter sample of hydrochloric acid are used in a chemical reaction. Which combination of
2 answers:
Answer:
(4) zinc powder and 3.0 M HCl(aq)
Explanation:
First consider the equation of reaction:
1 mole of Zinc requires 2 moles of HCl for reaction.
mole of zinc = mass/molar mass = 5.0/65.38 = 0.0765 mole
0.0765 mole of zinc will require: 0.0765 x 2 = 0.1530 mole HCl
Mole of 1.0 M HCl = Molarity x volume = 1 x 0.05 = 0.05 mole
Mole of 3.0 M HCl = 3 x 0.05 = 0.15
Hence, the 3.0 M HCl is what will give the required number of mole.
<em>Zinc in powder form will react faster compared to in strip because the former has higher surface area for reaction.</em>
Therefore, zinc powder and 3.0 M HCl will give the fastest reaction rate.
<em>The correct option is option 4.</em>
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Answer:
The correct option is;
2) Thermal energy increases by a factor of R
Explanation:
The equipartition energy theorem states that when molecules are in a state of thermal equilibrium, particles within the system posses equal average energy with each degree of freedom which can be known as energy due to a state of having a particular temperature or thermal energy given by the relation
= Kinetic energy of translation + Kinetic energy of rotation + Energy of vibration
For a mono-atomic gas, = 3/2·n·R·T
For a diatomic gas, = 5/2·n·R·T
For a solid element, = 3·n·R·T
Therefore, as the temperature is doubled, the thermal energy increases by a factor of R.