Answer:
ΔH2=772 kJ
Explanation:
Hello,
In this case, since the change in a reaction's enthalpy is given by the subtraction between the product's enthalpies and the reactant's enthalpies, we notice that the second reaction is the same initial reaction but arranged on the contrary way. In means that if the original reaction has:
ΔH1=−772 kJ
It means that the reaction:
2NaCl → 2Na + Cl2
Has an enthalpy of reaction of:
ΔH2=-(−772 kJ)
ΔH2=772 kJ
As the reactants and products were all inverted, so the enthalpy change has the same number but different sign.
Best regards.
its A, calcium chloride has a higher boiling point than sucrose
The answer is sublimation.
Sublimation is the chemical process whereby a solid turns into a gas without first becoming a liquid.
The word sublimation comes from the Latin word sublimare which means "raised to a higher status."
Examples of sublimation include surface layer of snow and ice turning into steam or fog without melting and dry ice which is the solid form of carbon dioxide which also undergoes sublimation.
The low temperature and sublimation makes dry ice an effective coolant or cooling agent . One of its main advantages is that it has a lower temperature than water ice and also does not leave any residue.
Answer:
2.1 atm
Explanation:
We are given the following variables to work with:
Initial pressure (P1): 2.5 atm
Initial temperature (T1): 320 K
Final temperature (T2): 273 K
Constant volume: 7.0 L
We are asked to find the final pressure (P2). Since volume is constant, we want to choose a gas law equation that relates initial pressure and temperature to final pressure and temperature. Gay-Lussac's law does this:
We can rearrange the law algebraically to solve for 
.
Substitute your known variables and solve:
Convection
Convection is transfer of heat through fluid (liquid or gas) caused by their molecular motion. In convection, heat current flows in a vertically upward direction. Macaroni rising and falling in a pot of boiling water is due to convection
