Answer:
I) Change in solubility
II) Change in boiling point
III) Change in colour
Explanation:
A chemical change involves formation of new products and is not reversible.
So, once two liquid solutions are mixed and a chemical change takes place, the new product will have the following:
- a new solubility rate, i.e it will dissolve at a rate different from the two liquid solution
- a new boiling point i.e it takes a new point at which its molecules liberate to yield vapour
- a new colour might be detected, as the individual solution each has its own colour
Answer:
Molecule.
Explanation:
carbon and fluorine. Based on the bonding, a unit of carbon dioxideis described as a molecule.
Answer:
D
Explanation:
wavelength = speed of light/ frequency
= (3 x 10^8 m/s) / (3 x 10^12 Hz)
= 1 x 10^-4 m
<u>Answer:</u> For the given equation, only iron has the value of
equal to 0 kJ.
<u>Explanation:</u>
Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as 
The equation used to calculate enthalpy change is of a reaction is:
![\Delta H^o_{rxn}=\sum [n\times \Delta H^o_f(product)]-\sum [n\times \Delta H^o_f(reactant)]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H%5Eo_f%28product%29%5D-%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H%5Eo_f%28reactant%29%5D)
For the given chemical reaction:

The equation for the enthalpy change of the above reaction is:
![\Delta H^o_{rxn}=[(1\times \Delta H^o_f_{(Fe(s))})+(3\times \Delta H^o_f_{(CO_2(g))})]-[(3\times \Delta H^o_f_{(CO(g))})+(2\times \Delta H^o_f_{(Fe_2O_3(s))})]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B%281%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28Fe%28s%29%29%7D%29%2B%283%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28CO_2%28g%29%29%7D%29%5D-%5B%283%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28CO%28g%29%29%7D%29%2B%282%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28Fe_2O_3%28s%29%29%7D%29%5D)
The enthalpy of formation for the substances present in their elemental state is taken as 0.
Here, iron is present in its elemental state which is solid.
Hence, for the given equation, only iron has the value of
equal to 0 kJ.
A balance in a lab measures the weight of a substance or object.
Weight is the mass of the body x the gravitation pull on the mass of the object.
So the mass of the object can be found by dividing the weight by gravitational constant.
The gravitational constant on earth is 1. so if a balance says that a substance weighs 300g then its mass is also 300g on earth because 300/1 = 300.
Hope that helps :)