Carbonate Equation

How much Fe++ could be present in water containing 1.2 x 1e-02 M HCO3- (bicarbonate) without causing the precipitation of FeCO3 (Ksp=10**(-10.7)) Hint: carbonate equation.

Picograms

Im confused on how to do this problem all together. I can't find help in the book because their answers are hard to follow. If you could work this out and explain how each step was done so I could understand how to do it that would be awesome. Thank you Given that the average TEQ of animal-based foods is about 0.7 picograms of TCDD equivalent per gram, and that the LD50 for 2,3,7,8-TCDD is about 0.001 mg/kg body weight, what mass(kg) of animal-based food would you have to consume to ingest a fatal dose of it?

How many oxygen atoms are indicated in one formula unit of each of the following?

Please help with the following problems. 1. How many oxygen atoms are indicated in one formula unit of each of the following? a. Al2(C2O4)3 b. Ca3(PO4)2 c. Zn3(PO4)2 d. Al2(SO4)³ 2. How many atoms of each kind (N, P, H and O) does the notation 6(NH4)2HPO4 indicate? 3. Which of the following equations are balanced? a. 2 KNO3 + 10K → 6K2O + N2 b. 2 NH3 + O2 → N2 + 3 H2O c. 4BF3 + 3H2O → H3BO3 + 3HBF4 d. 3 CI2 +6NaOH → 5NaC1 +NaC1O3 + 3 H2O 4. Balance the following equations. a. MnO2 + HCl → MnCl2 + Cl2 + H2O b. Fe +O2 → Fe3O4 c. C5H12 + O2 → CO2 +H2O 5.... click for more

Toxicity of TCDD in Animal Based Foods

Given that the average TEQ of animal-based foods is about 0.7 picograms of TCDD equivalent per gram, and that the LD50 for 2,3,7,8-TCDD is about 0.001 mg/kg body weight, what mass(kg) of animal-based food would you have to consume to ingest a fatal dose of it?

A 40.0 mL sample of river water was titrated with 0.0010 M Na2Cr2O7 and required 8.3 mL to reach the end-point.

Could you please explain what formula and step are involved and please provide (example) problem if possible: A 40.0 mL sample of river water was titrated with 0.0010 M Na2Cr2O7 and required 8.3 mL to reach the end-point. What is the chemical oxygen demand, in milligrams of O2 per liter, of the sample?