Answer:
From the following enthalpy of reaction data and data in Appendix C, calculate ΔH∘f for CaC2(s): CaC2(s)+2H2O(l)→Ca(OH)2(s)+C2H2(g)ΔH∘=−127.2kJ
ΔHf°(C2H2) = 227.4 kJ/mol
ΔHf°(H2O) = -285.8 kJ/mol and
ΔHf°(Ca(OH)2) = -985.2 kJ/mol
(Ans)
ΔHf° of CaC2 = -59.0 kJ/mol
Explanation:
CaC2(s) + 2 H2O(l) → Ca(OH)2(s) + C2H2 (g) = −127.2kJ
ΔHrxn = −127.2kJ
ΔHrxn = ΔHf°(C2H2) + ΔHf°(Ca(OH)2) - ΔHf°(CaC2)- 2ΔHf°(H2O);
ΔHf°(CaC2) = ΔHf°(C2H2) + ΔHf°(Ca(OH)2) - 2ΔHf°(H2O) – ΔHrxn
Where
ΔHf°(C2H2) = 227.4 kJ/mol
ΔHf°(H2O) = -285.8 kJ/mol and
ΔHf°(Ca(OH)2) = -985.2 kJ/mol
ΔHf°(CaC2) =227.4 - 985.2 + 2x285.8 + 127.2 = -59.0 kJ/mol
ΔHf°(CaC2) = -59.0 kJ/mol
Answer:
Henry Moseley.
Explanation:
Hello,
Henry Moseley's work stated that it is better to organize the periodic table in the light of the atomic number (which accounts for the amount of protons and electrons) instead of the atomic mass, because atomic numbers are not arbitrarily assigned as long as they have the aforesaid physical basis.
Best regards.
Answer:
6.It is concluded that while high temperature has an unfavourable effect on seed set of radish plants, it also weakens the incompatibility reaction between pollen and style, so that the result is a small increase in yield.
7.The result of the study showed that music with a higher intensity is more distracting and has a greater effect on task performance and concentration. The result helped formulate the Attention Drainage Effect theory, which is based on Kahneman's (1973) capacity model of attention
8. If the food is more colorful then the fish will eat more because they're more interested in the colors
9.If plants do not receive enough light, they will not grow at their maximum rate or reach their maximum potential, regardless of how much of any other variable – water, growth medium or fertiliser – they receive. Light is the driving force for photosynthesis, a plant process that changes sunlight into chemical energy. Plants need five things in order to grow: sunlight, proper temperature, moisture, air, and nutrients. These five things are provided by the natural or artificial environments where the plants live. If any of these elements are missing they can limit plant growth.
The independent (or manipulated) variable is something that the experimenter purposely changes or varies over the course of the investigation. The dependent (or responding) variable is the one that is observed and likely changes in response to the independent variable.
10.What effect does smiling have on a teacher giving no homework.
Hypothesis
If a student smiles at teacher, then no homework will be assigned
independent variable is smiling
dependent variable is homework
Explanation:
The suffix -ene tells that there is a double bond present in the molecule, and the 2 tells where in the molecule the bond is located. The molecule looks like this:
CH3-CH=CH-CH3
-ane indicates single bonds
-ene indicates at least one double bond
-yne indicates at least one triple bond
Ο₂ + 2H₂ => 2H₂O
oxygen is limiting reactant. excess hydrogen
So answer is 8moles of water