Answer:
element.
.it is pure substance composed of only one type of atoms.
.the number of element is more than 118.
compound.
.a compound is composed of atoms of two or more elements.
.the number of compound is very large in comparison of elements.
hope it help
Answer:
0.534
Explanation:
Mole fraction can be calculated using the formula:
Mole fraction = number of moles of solute ÷ number of moles of solvent and solute (solution).
In this question, solute is dimethyl ether while the solvent is methanol.
Mole (n) = mass (M) ÷ molar mass (MM)
Mole of solute (dimethyl ether) = 148.5 ÷ 46.07
= 3.22moles.
Mole of solvent (methanol) = 90 ÷ 32.04
= 2.81moles.
Total moles of solute and solvent = 3.22 + 2.81 = 6.03moles.
Mole fraction of dimethyl ether = number of moles of dimethyl ether ÷ number of moles of solution (dimethyl ether + methanol)
Mole fraction = 3.22/6.03
= 0.534
Your mass can never change no matter where you are since mass is the amount of matter you contain. By going to the moon, you do become lighter due to the weaker gravity but the amount of matter that you are made of (your mass) does not change.
I hope the helps. Let me know if anything is unclear.
Explanation:
Galileo found Venus went through the entire phase cycle, proving that she revolved completely around the Sun, as predicted by Copernicus in his heliocentric model. ... The phases of Venus could not be explained by Ptolemy's Geocentric Model. Galileo knew that the Roman Catholic Church was incorrect.
Answer:
The nonmetals in Groups 15, 16, and 17 form ions with charges of 3-, 2-, and 1-, respectively.
Explanation:
The elements of Group 18 (the noble gases) have a complete valence shell of eight electrons.
It is <em>easier</em> for the elements of Groups 15 to 17 <em>to</em> <em>gain</em> three, two, or one electron(s) to get a complete valence shell <em>than it is to lose</em> five, six, or seven valence electrons.
Thus, they form <em>negative ions</em> with charges of 3-, 2-, and 1-, respectively.
The charges <em>do not correspond</em> to the Group numbers of 15 to 17 or the old (pre-1990) Group numbers of 5A to 7A.