Answer:
. A closed system allows only energy transfer but no transfer of mass. Example: a cup of coffee with a lid on it, or a simple water bottle. ... In reality, a perfectly isolated system does not exist, for instance hot water in a thermos flask cannot remain hot forever.
Answer: 41.5 mL
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
where,
n = moles of solute
= volume of solution in L
Given : 59.4 g of 
in 100 g of solution
moles of 
Volume of solution =
Now put all the given values in the formula of molality, we get
To calculate the volume of acid, we use the equation given by neutralisation reaction:
where,
are the molarity and volume of stock acid which is
are the molarity and volume of dilute acid which is
We are given:
Putting values in above equation, we get:
Thus 41.5 mL of the solution would be required to prepare 1550 mL of a .30M solution of the acid
Answer- A
Explanation- Because you have to look at the symbols and remember which symbol goes with each chemical, if you don't then you could get confused.
CFCs and their associated compounds were developed in the early 1900s as a non-toxic, non-flammable solution to other more dangerous products such as ammonia.
D. electro magnetic waves. it’s literally in the name
