Answer: Option (d) is the correct answer.
Explanation:
A reaction in which there occurs change in oxidation state of reacting species is known as an oxidation-reduction reaction.
(a) 
Will be written as:
In this reaction, there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(b) 
Will be written as:
Similarly here, there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(c) 
Will be written as:
Here, also there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(d) 
So, here there occurs change in oxidation state of Mg from 0 to +2 and oxidation state of H changes from +1 to 0. Hence, it is an oxidation-reduction reaction.
Thus, we can conclude that is an oxidation-reduction reaction.
Answer:
its A screw :))) your welcome
I did this question before and the answer is Magnesium and silicon, B.
Depends on where the object is. On earth, moon , or somewhere without any other mass (theoretically). I think you mean how much does weigh on earth. So, the average gravitational acceleration on earth is : 9.83 m/s^2 To find out how much an object weighs, this is the formula : G=m.g where m is mass of the object g is the gravitational acceleration and G is weight. So, G = 10.9,83 = 98,3 N is the answer.
Answer:
The mechanical energy produced on burning fossil fuels is transformed into chemical energy stored in carbon dioxide.
Explanation:
When fossil fuels are burnt, mechanical energy is produced. Remember that according to the first law of thermodynamics, energy is neither created nor destroyed but can be transformed from one form to another. Hence the mechanical energy produced when fossil fuels are burnt for industrial use, heating of homes, electricity generation , cooking etc the mechanical energy produced is not 'lost'. It must be transformed in to another form of energy.
In the image the arrow G----> C, shows the mechanical energy produced when fossil fuels are burnt are stored as chemical energy in CO2 bonds. CO2 is found in the atmosphere, hence the arrow point upwards from the source towards the atmosphere (C is the atmospheric reservoir of CO2). The energy is subsequently used by producers to produce chemical energy stored in food.
