Answer:
42.0×10² second²
Explanation:
Here, time is given in milisecond
(64800 ms)²
= 4199040000 ms²
The SI unit is seconds
1 second = 1000 milisecond



42.0×10² second²
Answer:
first question is 178 g of sodium phosphate dihydrate. second question is 0.25 mL
Explanation:
To know the number of grams from the number of moles
. 1 mol is equal to 178 g. Second question mL of the stock is obtained from
.
There is too much information given, it's hard to understand exactly which variables are important in this problem.
It has a 10 electrons. Since it's atomic number is 11 it must have 11 protons. Also, given that it has a +1 charge, it has one less electron than protons since they have equal but opposite charges.
The number of protons is the mass number minus the atomic number = 23-11= 12 neutrons.
Answer:
0.0321 g
Explanation:
Let helium specific heat 
Assuming no energy is lost in the process, by the law of energy conservation we can state that the 20J work done is from the heat transfer to heat it up from 273K to 393K, which is a difference of ΔT = 393 - 273 = 120 K. We have the following heat transfer equation:

where
is the mass of helium, which we are looking for:
