Answer:
B. materials change their properties.
Explanation:
In a chemical change, materials often change their properties because a re-arrangement of atoms takes place.
A chemical change is one in which new kind of matter is formed.
It is always accompanied by energy changes.
- Chemical changes are not reversible.
- They lead to the production of new kinds of matter
- It involves mass changes
- Requires considerable amount of energy
Answer:
a) ΔGº= -49,9 KJ/mol = - 50 KJ/mol
b) The reaction goes to the right to formation of products
c) ΔG= 84,42 KJ/mol. The direction is to reactive, to the left
Explanation:
a) ΔGº= - RTLnKf
You need to convert Cº to K. 25ºC=298K
Then, ΔGº= - 3,814 J/molK * 298K* Ln(5.6 *10^8)= - 49906 J/mol = -49,9 KJ/mol = - 50 KJ/mol
b) The ΔGº < 0, that means the direct reaction is spontaneous when te reactive and products are in standard state. In other words the reaction goes to the right, to formation of products
c) The general ecuation for chemical reaction is aA + bB → cD + dD. Thus
ΔG=ΔGº + RTLn (([C]^c*[D]^d)/[A]^a*[B]^b)
In this case,
ΔG=ΔGº + RTLn ([Ni(NH3)62+] / [Ni2+]*[NH3]^6 )= 84417 J/mol =84,42 KJ/mol
ΔG >0 means the reaction isn't spontaneous in the direction of the products. Therefore the direction is to reactive, to the left
Answer:
Element.
Explanation:
Aluminum is an element because it is not separable into simpler substances. One thing important to keep in mind is that if something is on the Periodic Table of Elements, it is 100% an element.
A hair dryer converts "electrical energy" to "thermal energy".
Option: C
<u>Explanation</u>:
The "electricity" is converted to "heat energy" in a "wire coil". Here electricity process "air" out of "the hair dryer" with the help of forced convection. Most hairdryers use a nichrome wire coil that will not oxidize when heated and allowing it to "blow" the hair dry with high temperature air which speeds up evaporation. Thus "wire heats" the "air faster", in most of the "hair dryers" the "air" is only in "the barrel" for "half of a second".
Answer:
* The empirical formula of a compound shows the ratio of elements present in a compound
* The molecular formula of a compound shows how many atoms of each element are present in a molecule of a compound.
Example: the compound butene has a molecular formula of C4H8. The empirical formula
of butene is CH2 because there is a 1:2 ratio of carbon atoms to hydrogen atoms.
