Answer:
i think it is chemical wait no physical
Explanation:
Silicon is a popular semi-conductor. The process of doping either creates an excess or lack of electrons. In the case of silicon, the dopant is arsenic which has greater valence electron than silicon. Arsenic then donates an electron resulting to an excess of electrons. A new type or better type of semi-conductor is created. Silicon conduct greater electricity.
The best answer is the last option.
What's the problem ? Hardness is not the definition of a metal.
You need to expand your thinking. EVERY element is solid, liquid, and gas, over different ranges of temperature ... including all of the metals. There are only TWO elements that are liquid AT ROOM TEMPERATURE, and mercury is one of them. But on a mild day at the south pole, mercury is solid too.
Answer:
14 J of heat
Explanation:
Recall that the enthalpy of reaction is defined as the enthalpy change that occurs in a system when matter is transformed by a given chemical reaction, if all reactants and products are in their standard states. Here we have the heat of formation of six moles of the substance and we are expected to use it to obtain the the heat of formation of one mole of the compound and we can do that by simple proportion as shown below;
If 6 moles of the compound produces 84J of heat
1 mole of the substance will produce 1×84/6 = 14 J of heat
An environmental scientist studies the environment - you can see that in the beginning of the sentence :)
