(1) To make NaTcO4, Tc metal is dissolved in nitric acid to make HTcO4, NO2 and H2O. Then the product HTcO4 is treated with NaOH to make NaTcO4. If you begin with 4.5 mg of Tc metal, how much of NaOH (in grams) is required to convert all of the HTcO4 into NaTcO4?
Tc + 7HNO3 = HTcO4 + 7NO2 + 3H2O
HTcO4 + NaOH = NaTcO4 + H2O
I used these to find the answer.... 0018 g NaOH.
(2)Explain how to prepare zinc chloride by a) acid-base reaction or b) a gas formation reaction. The starting materials available are ZnCO3, HCL, CL2, HNO3, NaCL, Zn(NO3)2, and Zn.
(a) ZnCO3(aq) + 2HCl(aq) ---> ZnCl2(aq) + H2O(l) + CO2(g); ZnCO3 is a base, HCl is an acid.
(b)Zn + HCl --> ZnCl2 + H2; H2 is a gas.
The three answers (NaOH problem + 2 equations) look ok to me.
To answer the first question, you need to find the amount of NaOH required to convert all of the HTcO4 into NaTcO4.
The reaction equation given is:
HTcO4 + NaOH = NaTcO4 + H2O
First, you need to find the molar mass of Tc metal. Tc (Technetium) has a molar mass of approximately 98 g/mol.
You are given that you have 4.5 mg of Tc metal. To convert this to grams, divide by 1000:
4.5 mg / 1000 = 0.0045 g Tc
Next, you need to convert grams of Tc to moles. To do this, divide the mass by the molar mass:
0.0045 g Tc / 98 g/mol = 4.59 × 10^-5 mol Tc
From the balanced chemical equation:
1 mol HTcO4 requires 1 mol NaOH
Therefore, the moles of NaOH required is also 4.59 × 10^-5 mol.
To find the mass of NaOH required, you need to multiply the moles by the molar mass of NaOH.
The molar mass of NaOH is approximately 40 g/mol.
Mass = moles × molar mass = 4.59 × 10^-5 mol × 40 g/mol = 0.0018 g NaOH
So, the answer is 0.0018 grams of NaOH is required to convert all of the HTcO4 into NaTcO4.
For the second question, you are asked to explain how to prepare zinc chloride using both an acid-base reaction and a gas formation reaction.
(a) In an acid-base reaction, you need a base to react with an acid to form the salt. In this case, you have ZnCO3 (zinc carbonate) as the base and HCl (hydrochloric acid) as the acid. The reaction would be:
ZnCO3(aq) + 2HCl(aq) ---> ZnCl2(aq) + H2O(l) + CO2(g)
This reaction will produce zinc chloride (ZnCl2), water (H2O), and carbon dioxide (CO2) as products.
(b) In a gas formation reaction, you need a reactant that can produce a gas when it reacts with another substance. In this case, zinc (Zn) reacts with hydrochloric acid (HCl) to form zinc chloride (ZnCl2) and hydrogen gas (H2):
Zn(s) + 2HCl(aq) ---> ZnCl2(aq) + H2(g)
In this reaction, zinc chloride (ZnCl2) and hydrogen gas (H2) are produced.
You have multiple starting materials available, including ZnCO3, HCl, Cl2, HNO3, NaCl, Zn(NO3)2, and Zn. However, from the given options, only zinc carbonate (ZnCO3) and hydrochloric acid (HCl) are suitable for both the acid-base and gas formation reactions to prepare zinc chloride.