Answer: Decreases the rate of reaction
- Remove water from food by dehydration.
- Transport food in a refrigerated truck.
- Store food in airtight containers.
- Store food in a refrigerator after opening.
Does not decrease the rate of reaction
- Store food in the open air.
- Place food on a warm surface.
Explanation: Dehydration of food excludes water from food which is one of the factor needed by microorganisms for growth, <em>so it decreaese the rate of reaction.</em>
Transporting food in refrigerated trucks lowers the temperature of food and not many microorganisms are active at very low temperatures, so it <em>decreases the rate of reaction.</em>
Storing food in airtight containers excludes air which is one of the factors required for microbial activity, so <em>it decreases reaction rate.</em>
Storing food in refrigerators after opening also <em>lowers the temperature of food and hence the the rate of microbial activit</em>y.
Storing food in the open air <em>does not decrease microbial activity</em> instead it provides microorganisms with the favorable conditions for their activity such as air and water from water vapor in the air.
Placing food on a warm surface <em>does not decrease rate of reaction</em> because microorganisms are very active in warm and humid environments.
The answer to your question is a
Explanation:
It is known that efficiency is denoted by 
.
The given data is as follows.
= 0.82, 
= (21 + 273) K = 294 K
= 200 kPa, 
= 1000 kPa
Therefore, calculate the final temperature as follows.
0.82 = 
= 1633 K
Final temperature in degree celsius = 
= 
Now, we will calculate the entropy as follows.
For 1 mole, 
It is known that for 
the value of 
= 0.028 kJ/mol.
Therefore, putting the given values into the above formula as follows.
= 
= 0.0346 kJ/mol
or, = 34.6 J/mol (as 1 kJ = 1000 J)
Therefore, entropy change of ammonia is 34.6 J/mol.
Calcium ions have oxidation state 2+ => Ca (2+).
Bromime ions (bromide) have oxidation state 1- => Br (-).
So, to be neutral the compound has to have two Br (-) ions per each Ca(2+) ion.
That is represented in the chemical formula as Ca Br2, where the number 2 to the right of Br is a subscript meaning that there are two atoms of Br per each atom of Ca (the lack of subscript means 1 atom).
Answer: Ca Br2.
