Answer:
B. Libra
Explanation:
Libra's range from September 23rd to October 22nd
Answer:
Explanation:
Building Vocabulary
Match each term with its definition by writing the letter of the correct definition on
the line beside the term in the left column.
5. nucleus b
6. proton f
7. neutron h
8. electron d
9. atomic number g
10. isotopes c
11. mass number a
12. energy level e
a. the sum of protons and neutrons in the nucleus of an
atom
b. the very small center core of an atom
c. atoms of the same element that differ in the number
of neutrons, but have the same number of protons
d. the particle of an atom that moves rapidly in the
space outside the nucleus
e. a specific amount of energy related to the movement
of electrons in atoms
f. the particle of an atom with a positive charge
g. the number of protons in the nucleus of every atom
of an element
h. the particle of an atom that is neutral
-. mass number a.
12. energy level e
Answer:
no, the correct answer is NaCI
Explanation:
you're welcome
The empirical formula for a compound is KClO3
Explanation
find the moles of each element
moles = % composition/molar mass
molar mass of of potassium =39g/mol ,chlorine = 35.5 g/mol, oxygen =16 g/mol
moles of potassium = 31.9 / 39 = 0.818 moles
moles of chlorine = 28.9/35.5 = 0.814 moles
moles of oxygen = 39.2/ 16 = 2.45 moles
find the mole ratio by dividing with the smallest mole = 0.814 moles
potassium = 0.818/0.814 =1
chlorine = 0.814/0.814 = 1
oxygen = 2.45 /0.814 =3
the empirical formula is therefore = KClO3
Methane is the compound CH4, and burning it uses the reaction:
CH4 + O2 -> CO2 + H2O, which is rather exothermic. To find the heat released by burning a certain amount of the substance, you should look at the bond enthalpy of each compound, and then compare the values before and after the reaction. In methane, there are 4 C-H bonds, which have bond energy of 416 kj/mol, resulting in a total bond energy of 1664 kj/mol. O2 is 494 kj/mol. Therefore we have a total of 2080 kj/mol on the left side. On the right side we have CO2, which has 2 C=O bonds, each at 799 kj/mol each, resulting in 1598 kj/mol, and H2O has 2 O-H bonds, at 459kj/mol each, resulting in a total of 2516 kj/mol on the right hand side. Now, this may be confusing because the left hand side seems to have less heat than the right, but you just need to remember: making minus breaking, which results in a total change of 436kj/mol heat evolved.
Now it is a simple matter of find the mols of CH4 reacted, using n=m/mr.
n = 9.5/16.042 = 0.592195 mol
Therefore, if we reacted 0.592195 mol, and we produced 436 kj for one mol, the total amount of energy evolved was 436*<span>0.592195 kj, or 258.197 kj.</span>