Answer:
hair is a physical change.
Cooking is a physical and chemical change.
Ice cream melting in the sun is a physical change.
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Answer:
This question begins with something, you should know: molar mass from water is aproximately 18 g/m, so if 18 grams of water are contained in 1 mole, the 40 grams occuped 2.22 moles. As you see, opcion a is the best!
Explanation:
It might calculate the volume, but you need the length as well, depending on the object.
Answer:
1384 kJ/mol
Explanation:
The heat absorbed by the calorimeter is equal to the heat released due to the combustion of the organic compound. C is the total heat capacity of the calorimeter and Δt is the change in temperature from intial to final:
Q = CΔt = (3576 J°C⁻¹)(30.589°C - 25.000°C) = 19986.264 J
Extra significant figures are kept to avoid round-off errors.
We then calculate the moles of the organic compound:
(0.6654 g)(mol/46.07) = 0.0144432 mol
We then calculate the heat released per mole and convert to the proper units. (The conversion between kJ and J is infinitely precise and is not involved in the consideration of significant figures)
(19986.264 J)(1kJ/1000J) / (0.0144432 mol) = 1384 kJ/mol
Explanation:
- The boiling point of Potassium is most similar to the element sodium , since , both the elements belong to the same group i.e. , the group one , Hence , the most of the physical chemical properties are same , irrespective of some exceptions .
Hence , the Boiling point of Potassium and sodium are the same .
- The boiling point of Potassium is least similar to the element helium , since , both the elements belong to different groups , Since , Helium has a negative boiling point and is one of the most stable element , being a noble gas .
