Answer: A chemical process must occur and then changes between the state of the reactants and the state of the products can be determined
Explanation: Enthalpy represents the sum of the energy of the system with the product of the pressure and volume of that system. As a thermodynamic property, it expresses the ability to release heat from the system. In fact, enthalpy tells us how much heat and work has changed during the chemical reaction under constant pressure. When measuring, measurements of the difference in enthalpy between the two states of the system is performed, before and after the chemical reaction, since total enthalpy can not be measured. This measurement of the enthalpy change can tell us, for example, whether the heat was released from the system during the reaction, or the system absorbed the heat.
The molarity and normality of 5.7 g of Ca(OH)2 in 450ml 0f solution is calculated as follows
molarity = moles/volume in liters
moles =mass/molar mass
= 5.7g/74g/mol = 0.077moles
molarity = 0.077/450 x1000= 0.17M
Normality = equivalent point x molarity
equivalent point of Ca(OH)2 is 2 since it has two Hydrogen atom
normality is therefore = 0.17 x2 = 0.34 N
<span>1) Boiling water for pasta-> physical
2) Digesting food -> chemical
3) Soda goes "flat" -> physical
4) Stretching a rubber band -> physical
5) Grilling a hamburger -> chemical
6) Adding sugar to tea -> physical
7) Adding lemon to tea -> physical
8) Mowing the grass -> physical
9) The smell of perfume "wafts" across the room -> physical
10) Candle wax melts -> physical
11) Breaking glass-> physical
12) Making cement-> chemical
13) Lighting a match-> chemical
14) Water is absorbed by a paper towel-> physical
15) Firefly glows in the dark-> chemical
16) Snow melts-> physical
17) Bleaching your hair-> chemical
18) Turning on a light bulb-> physical
19) Milk goes sour-> chemical
20) Shooting off fireworks-> chemical</span>
Answer: The volume of sample at 400 K is 
Explanation:
Charles' Law: This law states that volume is directly proportional to the temperature of the gas at constant pressure and number of moles.
(At constant pressure and number of moles)
where,
= initial volume of gas = 
= final volume of gas = ?
= initial temperature of gas = 360 K
= final temperature of gas = 400 K
Putting in the values we get:
Thus volume of sample at 400 K is
