Answer:
a)
⇒
⇒
b)
⇒
⇒
Explanation:
A)
Remember that positive number superscripts mean electrons lack and negative numbers mean electrons 'excess' (if we compare it with the neutral element). So, for the case of Fe2+ which is converted to Fe3+, we know that in Fe2+ there is a two electrons lack, while in Fe3+ there is a 3 electrons lack; it means that Fe2+ was converted to Fe3+ but releasing one electron:
⇒
The same analysis is applied to Br2; Br2 is a molecule which is said to have a zero superscript because it is an apolar covalent bond; and it is converted to Br-, which, according to what I wrote above, means that there is a one electron excess. So, Br2 must have received an electron in order to change to Br-; but Br2 can't change to Br- as simple as that because Br2 is a molecule, not an atom; it is a molecule that has two Br atoms, so, Br2 must give two Br- ions as products, but receiving one electron for each one:
⇒
b)
Applying the same, in Mg2+ there is a 2 electrons lack, and in Mg is not electron lack (its superscript is zero), so Mg must have released two electrons in order to change to Mg2+:
⇒
Cr3+ has a 3 electrons lack, and Cr2+ a two electrons one, so, Cr3+ must receive an electron to convert to Cr2+:
⇒
Answer:
The direction will be changed
.
Explanation:
According to the principles of motion, if an object is moving with solitary velocity and if an external force is applied to it, then that force changes the position, speed, and direction of that object.
In the given question, an external force is being applied to the toy which will change the direction of that toy.
Answer:
The answer is carbon cycle.
Explanation:
The carbon cycle is an important process for living organisms. As plants prepare their food through photosynthesis and is also an important source of fossil fuels for human activities.
Therefore carbon atoms are regenerated again and again in the carbon cycle process. This recycling process takes place between livings and nonliving things in the environment and also within the earth biosphere.
Abundance supply of carbon is necessary to carry out the biological processes. The entire carbon cycle is actually made up of sourced and sinks elements.
Explanation:
The reaction between calcium hydroxide and nitric acid is as follows.
Number of reactant atoms are as follows.
Number of product atoms are as follows.
To balance the given chemical equation, multiply 
by 2 on reactant side and multiply 
by 2 on the product side.
Therefore, the balanced chemical equation will be as follows.
