Answer:
Physical change: A,C ,D, F, H, I
Chemical Change: B, E, G, J, K
Answer:
1. No 1 looks like a statement and not a question.
2.Ionic compounds are usually formed from the transfer of electrons from metals to Non metals. All others are Ionic compounds except HCl(Its a covalent compound).
3. The Formula would be K2S. Exchange of Radicals takes place. Sulphur has a -2 charge and potassium has a +1 charge. when they both exchange radicals... The compound is K2S.
4.Group 1 elements have only 1 electron in their outermost shell.
5. its charge will be +1 because it loses the 1 electron in its outermost shell.
6.Group 2 elements have 2electrons in their Valence shell.
7.Already answered. same as No 5.
8. Group 16;Also known as group 6. They have only 6 electrons in their outermost shell.
9.When they want to become stable... they acquire 2electrons to complete their octet... so they possess a -2 charge by forming an ion.
10. i)They form ions when Dissolve in solutions
ii) They are hard and brittle
iii) They have high boiling points
The answer is
<span>2PbS(s) + 3O2(g) = 2PbO(s) + 2SO2(g)
Your answer is not yet balanced because you have 3 oxygen atoms. it should be balanced by multiplying both side by 2 such as the balanced equation I made. To check it, I will explain why your answer is not yet balanced.
check: (from your equation)
</span> 1-Pb-1
1-S-1
2 -O-3
the difference between the reactant and the product of Oxygen will prove that it is not yet balanced.
If you use 2PbS(s) + 3O2(g) = 2PbO(s) + 2SO2(g), to check it:
2-Pb-2
2-S-2
6 -O-6
then this is now balance
The correct answer is:
A positively charged nucleus is surrounded by one or more negatively charged electrons
The explanation:
when:
proton is a positively charged elementary particle that is a fundamental constituent of all atomic nuclei.
neutron is a subatomic particle found in the nucleus of every atom except that of simple hydrogen. The particle derives its name from the fact that it has no electrical charge
electron is a negatively charged subatomic particle. It can be either free (not attached to any atom), or bound to the nucleus of an atom .
so, , there are positively charged protons and zero-charged neutrons in the nucleus of an atom. Therefore, the nucleus is positively charged, Surrounding the nucleus, the electrons have negative charge.
Thus, the correct answer is (3): A positively charged nucleus is surrounded by one or more negatively charged electrons is correct.
Answer:
25,050 calories.
Explanation:
A calorie is the amount of energy needed to raise the temperature of one gram of water 1 degree centigrade. If we are raising 835 grams of water 30 degrees then we multiply 835*30 to get 25,050 calories.
