The urinary system filters and gets rid of waste from the body.
First, the symbol for sodium oxide is Na₂O
Each Na (sodium) has a charge of 1+, and each O has a charge of 2- :
Na₂¹⁺O²⁻
There are two Na's, however, and each one is 1+, however, so the Na₂ has a total charge of 2+. Because of this, the 2+ from the 2 Na's and the 2- from the O cancel each other out to make 0.
The solid melts and becomes a liquid.
Answer: 72.4 kJ/mol
Explanation:
The balanced chemical reaction is,
The expression for enthalpy change is,
![\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f%28product%29%5D-%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f%28reactant%29%5D)
![\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+(n_{H_2O}\times \Delta H_{H_2O})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{C_3H_8}\times \Delta H_{C_3H_8})]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%28n_%7BCO_2%7D%5Ctimes%20%5CDelta%20H_%7BCO_2%7D%29%2B%28n_%7BH_2O%7D%5Ctimes%20%5CDelta%20H_%7BH_2O%7D%29%5D-%5B%28n_%7BO_2%7D%5Ctimes%20%5CDelta%20H_%7BO_2%7D%29%2B%28n_%7BC_3H_8%7D%5Ctimes%20%5CDelta%20H_%7BC_3H_8%7D%29%5D)
where,
n = number of moles
(as heat of formation of substances in their standard state is zero
Now put all the given values in this expression, we get
![-2220.1=[(3\times -393.5)+(4\times -241.8)]-[(5\times 0)+(1\times \Delta H_{C_3H_8})]](https://tex.z-dn.net/?f=-2220.1%3D%5B%283%5Ctimes%20-393.5%29%2B%284%5Ctimes%20-241.8%29%5D-%5B%285%5Ctimes%200%29%2B%281%5Ctimes%20%5CDelta%20H_%7BC_3H_8%7D%29%5D)
Therefore, the heat of formation of propane is 72.4 kJ/mol
Answer:
The answer to your question is d.
Explanation:
Chemical changes happen when the substance changes its original properties to form a new one. So option 1 is incorrect.
Dissolving a new substance does not form new substances as I mentioned before. The second option is incorrect.
The third option is also wrong because dissolving a substance does not separate anything.
The fourth option is correct, dissolving a substance allows us to make solutions.
