Answer:
A vacuum flask is usually used to insulate it's contents… I've used them for a multitude of things ranging from keeping my coffee warm, to keeping liquid nitrogen from evaporating.
The reason these types of flasks are so efficient has to do with their thermodynamic properties. To understand how a vacuum flask works, we need to know the basic properties of a vacuum. Air just like any other molecule is a conductor of heat.
Firstly, a “layer of vacuum” is created around the thermos, it's crucial that the chamber is depressurized*.
<u>Answer:</u> The temperature of the system will be 1622 K
<u>Explanation:</u>
The equation relating the pre-exponential factor and activation energy follows:
where,
D = diffusion coefficient =
= pre-exponential constant =
= activation energy of iron in cobalt = 273,300 J/mol
R = Gas constant = 8.314 J/mol.K
T = temperature = ?
Putting values in above equation, we get:
Hence, the temperature of the system will be 1622 K
Answer:
B. primary; secondary
Explanation:
Small changes in primary structure can result in large changes in protein shape and function. Secondary structure describes regions where the polypeptide is folded into localized shapes. There are two types of secondary structure (alpha helix and Beta pleated sheet).
Volume = Mass / Density
Volume = 147g / 1.010 g/ml
Volume = 146 ml
Answer: BF3
Explanation: boron needs 4 electron to obtain octet and Fluorine has just one. For the valence shell to be completely filled it will have to form BF4- with 4 fluorine atom surrounding it.