The heat of combustion<span> is the total energy released as </span>heat<span> when a substance undergoes complete </span>combustion<span> with oxygen under standard conditions. The chemical reaction is typically a hydrocarbon or other organic molecule reacting with oxygen to form carbon dioxide and water and release </span>heat<span>.
According to </span><span>Wikipedia :)</span>
Answer:
When the metal is dropped in the solution it turns blue to green because this forms iron sulphate solution and turns the metal copper
Iron sulphate + copper
The phonograph was invented for people with hearing problems. Option D is correct.
<h3>
What is a Phonograph?</h3>
- It is a device that records sounds or music in the grooves of a plate and plays them.
- This was the first invention that can record and play music.
- It was invented by Thomas Alva Edison.
- This device helps people with hearing problems by allowing them to practice concentrating on a different sound.
Therefore, the phonograph was invented for people with hearing problems.
Learn more about Phonograph:
brainly.com/question/858851