Fermentation
got it right on the test :)
Answer:
Calcium carbonate reacts with hydrochloric acid to form carbon dioxide gas. 2HCl (aq) + CaCO 3(s) CaCl 2 (aq) + CO 2(g) + H 2 O (l).
A. A pure chemical substance consisting of one type of atom
Answer:
a) ![_{31}^{71}\textrm {P^{3+}}](https://tex.z-dn.net/?f=_%7B31%7D%5E%7B71%7D%5Ctextrm%20%7BP%5E%7B3%2B%7D%7D)
b) ![_{35}^{80}\textrm {Br^{-}}](https://tex.z-dn.net/?f=_%7B35%7D%5E%7B80%7D%5Ctextrm%20%7BBr%5E%7B-%7D%7D)
c) ![_{90}^{232}\textrm {Th^{4+}}](https://tex.z-dn.net/?f=_%7B90%7D%5E%7B232%7D%5Ctextrm%20%7BTh%5E%7B4%2B%7D%7D)
d) ![_{38}^{87}\textrm {Sr^{2+}}](https://tex.z-dn.net/?f=_%7B38%7D%5E%7B87%7D%5Ctextrm%20%7BSr%5E%7B2%2B%7D%7D)
Explanation:
For neutral atoms:
Atomic Number (Z)= number of protons = number of electrons
Mass number (A) = number of protons + number of neutrons
For ions with positive net charge:
Number of protons = Z + net charge
For ions with negative net charge:
Number of protons= Z - net charge
a) A = 71, Charge = +3
Number of electrons = 28
Number of protons = 28 +3 =31
![_{31}^{71}\textrm {P^{3+}}](https://tex.z-dn.net/?f=_%7B31%7D%5E%7B71%7D%5Ctextrm%20%7BP%5E%7B3%2B%7D%7D)
b) A = 35, Z = 45+35=80, Charge = -1
Number of protons =35
Number of neutrons = 45
Number of electrons = 36
Charge = Number of protons- Number of electrons =35-36 = -1
![_{35}^{80}\textrm {Br^{-}}](https://tex.z-dn.net/?f=_%7B35%7D%5E%7B80%7D%5Ctextrm%20%7BBr%5E%7B-%7D%7D)
c) Charge = +4
Number of electrons = 86
Number of protons = Z = 86+4 = 90
mass number = A = 90+142 = 232
![_{90}^{232}\textrm {Th^{4+}}](https://tex.z-dn.net/?f=_%7B90%7D%5E%7B232%7D%5Ctextrm%20%7BTh%5E%7B4%2B%7D%7D)
d) Charge = +2
Atomic number = Number of protons = Z = 38
mass number = A = 87
![_{38}^{87}\textrm {Sr^{2+}}](https://tex.z-dn.net/?f=_%7B38%7D%5E%7B87%7D%5Ctextrm%20%7BSr%5E%7B2%2B%7D%7D)