Answer:
elements tend not to react with other elements, there were no oxide compounds for Mendeleev to study. –Group 18 elements are generally unreactive. sodium ion is smaller because the sodium atom lost one electron. –An Na+ ion is smaller because it has one fewer electron shell.
Explanation:
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Answer:
The mass of CO in 12,000 Liters of air is 
.
Explanation:
The ppm is the amount of solute (in milligrams) present in one Liter of a solvent. It is also known as parts-per million.
To calculate the ppm of oxygen in sea water, we use the equation:
The ppm concentration of CO = 10 ppm
Mass of CO = m
Volume of air = 12,000 L
The mass of CO in 12,000 Liters of air is .
Answer:
The answers are:
1) Latent heat of fusion
2) Heat is released
3) The process is endothermic
Explanation:
(1) The amount of energy required to freeze one kg of a substance is called latent heat of fusion.
(2) In a process, if heat is absorbed, the change in enthalpy for the substance is positive.
In a process, if heat is released, the change in enthalpy for the substance is negative.
The enthalpy of freezing for water is -6.02 kJ/mol. Heat is released as the enthalpy is negative.
(3) A positive value for enthalpy of vaporization indicates that the process is endothermic.
An exothermic process is one in which energy is released. The enthalpy for the process is negative.
An endothermic process is one which energy is absorbed. The enthalpy for the process is positive.
