127.88 grams of ethanol were present at the beginning of the reaction
Explanation:
Firstly, let's make the combustion reaction:
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
By 1 mol of ethanol, you can make 3 mole of water.
Mole of water = Water mass / Molar mass
150g / 18g/m = 8.3 mole
3 mole of water came from 1 mol of ethanol
8.3 mole came from (8.3 .1)/3 = 2.78 mole of ethanol
Molar mass ethanol = 46 g/m
Mole . molar mass = mass
2.78 m . 46g/m = 127.88 g
Answer:
The cyanidin indicator turns blue within a pH range of 5 - 7. The pH of the solution could be 5, 6 or 7.
An indicator is used to determine the endpoint of a titration.
Explanation:
Cyanidin indicator changes colour with each change in pH. In acidic solutions (pH < 7) cyanidin indicator will turn red, through to purple and blue, while in basic solutions (pH > 7), cyanidin indicator will change colour from aquamarine through to green and yellow. The cyanidin indicator turns blue within a pH range of 5 - 7.
Titration is a technique used in analytical chemistry to determine the unknown concentration of a solution. A solution of known concentration is added from a burette to the solution of unknown concentration until the reaction between the two solutions is complete. This known as the endpoint of the experiment. The endpoint of a titration is determined using an indicator which is added to reaction mixture. A colour charge is produced by the indicator at the endpoint of the reaction.
Note: An indicator is a dye of weak organic acids or bases which changes colour with changes in the pH of a solution. Some common indicators are methyl orange, methyl red, phenolphthalein, etc. These indicators are used to monitor the changes in the pH of solutions during a reaction.
Explanation:
The Absorption of Light by Chlorine, Bromine and their Gaseous Mixtures
<u>Answer:</u> The concentration of KOH solution is 1.215 M
<u>Explanation:</u>
For the given chemical equation:
To calculate the concentration of base, we use the equation given by neutralization reaction:
where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is KOH.
We are given:
Putting values in above equation, we get:
Hence, the concentration of KOH solution is 1.215 M
Corroding iron. The reason why iron corrodes is that it reacts with the oxygen in the air to create iron oxide which is what we call rust. when iron turns to rust, the chemical identity of the iron changes.
when you break ice, the ice is still ice. that water did not change into something else. when you run a current through copper, the electrons in the copper move due to the voltage but the copper is not changing. After the circuit stops, the copper wires are still made out of copper (the copper did not undergo a chemical change). When you melt gold, the gold is only going from solid form to liquid form. The gold has not changed chemically, it just underwent a phase change.
I hope this helps. Let me know if anything is unclear.
