Answer:
1.4 × 10^-4 M
Explanation:
The balanced redox reaction equation is shown below;
5Fe2+ + MnO4- + 8H+ --> 5Fe3+ +Mn2+ + 4H2O
Molar mass of FeSO4(NH4)2SO4*6H2O = 392 g/mol
Number of moles Fe^2+ in FeSO4(NH4)2SO4*6H2O = 3.47g/392g/mol = 8.85 × 10^-5 moles
Concentration of Fe^2+ = 8.85 × 10^-5 moles × 1000/200 = 4.425 × 10^-4 M
Let CA be concentration of Fe^2+ = 4.425 × 10^-4 M
Volume of Fe^2+ (VA)= 20.0 ml
Let the concentration of MnO4^- be CB (the unknown)
Volume of the MnO4^- (VB) = 12.6 ml
Let the number of moles of Fe^2+ be NA= 5 moles
Let the number of moles of MnO4^- be NB = 1 mole
From;
CAVA/CBVB = NA/NB
CAVANB = CBVBNA
CB= CAVANB/VBNA
CB= 4.425 × 10^-4 × 20 × 1/12.6 × 5
CB = 1.4 × 10^-4 M
B. because the other options are different sciences (biology and entomology)
Answer:
To equal the height of the Gateway Arch in St. Louis, it would take <u>76810 half dollars.
</u>
Explanation:
If the Gateway Arch in St. Louis is 630 feet high, how many half dollars will it take to equal the height if each half dollar is 2.15mm thick?
First, we convert the ft to cm and the cm to mm.
- 1 ft = 30.48 cm
630 ft = 19202.4 cm
- 19202.4 cm = 192024 mm
Now, if a half dollar is 2.15 mm thick, how many half dollars would it take to equal the height of 192024 mm?
1 half dollar = 2.15 mm
X = 192024 mm
X = 192024 mm / 2.15 mm
X = 76810 half dollars.
Hi my dear friend,
Because we must add heat, boiling water is a process that chemists call endothermic. Clearly, if some processes require heat, others must give off heat when they take place. ... Changes of state involve a solid melting, a liquid freezing, a liquid boiling or a gas condensing.
~Thank you
