Answer:
Potassium iodide increases the decomposition rate of hydrogen peroxide.
Explanation:
Potassium iodide increases the decomposition rate of hydrogen peroxide because potassium iodide act as a catalyst. A catalyst speed up the process of chemical reaction without reacting with the molecules present in reaction. If the potassium iodide is not present as a catalyst for the decomposition of hydrogen peroxide then the decomposition of hydrogen peroxide takes too much time because the catalyst is absent that speed up the reaction.
So in your question that ask to calculate the Ph result of the resulting solution if 26 ml of 0.260 M HCI(aq) is added to the following substance. The the result are the following:
A. The result is pH= 14-pOH
B. There are 10ml of 0.26m HCL excees in this reaction so the answer is log(H)+
Physical change does not make a new chemical/object. A chemical change does.
Chemical Change example: Combining liquid and liquid to create a new substance
1) Chemical reaction (thermal decomposition)
2NaHCO3 (s) ---> Na2CO3 (s) + H2O (g) + CO2(g)
2) Reasoning
The lost of mass is due to the lost of the gases H2O and CO2.
So, you can calculate the mass of Na2CO3 obtained from 1.000 g NaHCO3, and the difference will be the mass lost.
2) Convert 1.000 g of NaHCO3 to number of moles
molar mass NaHCO3: 1*23g/mol + 1*1g/mol + 1*12g/mol + 3*16g/mol = 84 g/mol
number of moles = mass in grams / molar mass = 1.000 g / 84 g/mol = 0.01190 moles
3) Use therotecial molar ratios:
2 moles NaHCO3 : 1 mol Na2CO3
=> 0.01190 mol NaHCO3 / x = 2 mol NaHCO3 / 1mol Na2CO3
=> x = 1mol Na2CO3 * 0.01190 mol NaHCO3 / 2 mol NaHCO3
=> x = 0.00595 mol Na2CO3
4) Convert 0.0595 mol Na2CO3 to mass
molar mass Na2CO3: 2*23g/mol + 1*12g/mol + 3*16g/mol = 106 g/mol
mass in grams = number of moles * molar mass = 0.00595 mol * 106 g/mol = 0.6307 g
5) lost mass
1.000g - 0.6307g = 0.3693 g
Answer: 0.3693 g
