It is not a pure substance, because a solution are mixed chemicals in a way that the molecules are not bonded with one another. Thus, separating them from compounds and elements, which are pure substances.
Answer:
20.2 kJ
Explanation:
Based on the information in the reaction, the amount of heat released per mole of Na₂O₂ (the molar enthalpy) is calculated as follows:
126 kJ / 2 mol = 63 kJ/mol Na₂O₂
The number of moles in 25.0g of Na₂O₂ must be calculated using the molecular weight of Na₂O₂ (77.978 g/mol):
(25.0 g)/(77.978 g/mol) = 0.32060 mol Na₂O₂
Thus, the heat released will be:
(63 kJ/mol)(0.32060 mol) = 20.2 kJ
Answer:
B. A reaction at equilibrium will respond to balance a change.
Explanation:
The Le Chatelier's principle states that a reaction will respond to balance a change. This is true for a reaction in chemical equilibrium.
Le Chatelier's principle sates that "if any conditions of a system in equilibrium is changed, the system will adjust itself in order to annul the effect of the change".
- It explains the effect of applying stress on any system in equilibrium.
- The changing conditions are usually concentration, temperature and pressure.
- If the stress due to any of them is applied to a system in equilibrium, the equilibrium will respond in the directions which counteracts the effect of the stress.
Answer:
134.8 seconds is the half-life (in seconds) of the reaction for the initial 
concentration
Explanation:
Half life for second order kinetics is given by:
Integrated rate law for second order kinetics is given by:
= half life
k = rate constant
= initial concentration
a = Final concentration of reactant after time t
We have :
Initial concentration of ![C_2F_4=[a_o]=\frac{0.438 mol}{2.42 L}=0.1810 mol/L](https://tex.z-dn.net/?f=C_2F_4%3D%5Ba_o%5D%3D%5Cfrac%7B0.438%20mol%7D%7B2.42%20L%7D%3D0.1810%20mol%2FL)
Rate constant = k = 
134.8 seconds is the half-life (in seconds) of the reaction for the initial concentration
