Answer:
25.9 g
Explanation:
Given that,
No of moles of calcium phosphate,
We need to find how many grams of calcium phosphate has this much of no of moles.
Mass divided by molar mass is equal to the no of moles on a molecule.
The molar mass of calcium phosphate is 310.18 g/mol
Using the concept of no of moles as follows :
Out of given options, option (a) i.e. 25.9 g is the correct answer.
Answer:
speed of plane in still air = 252 mph
speed of wind = 42 mph.
Explanation:
Given:
Distance travelled by the small plane = 245
Time taken to fly 245 miles = 1 hour and 10 minutes.
Time taken for return trip = 50 minutes.
To Find:
speed of the wind=?
The speed of the plane in still air=?
Solution:
We Know that
=>
=>
=>
=>210 mph against wind
on way back
=>
=>
=>
=> 294
Now
294 = plane +wind------------------------(1)
210 =plane - wind-------------------------(2)
Solving (1) and (2)
2 plane = 504
plane = 252
plane =
So substituting plane value in eq(2) we get,
210 =252 - wind
wind = 42 mph
Answer:
A
Explanation:
We are usually asked to close the valve of the gas cylinder in our various kitchens at home <u>due to the inflammable property of the Liquified Petroleum Gas.</u>
<em>Without closing the valve, the LPG would diffuse into our homes, and any form of spark would cause an explosion and lead to a fire. Lives and properties could be lost in the process.</em>
The correct option is A.
Answer:
The time required to melt the frost is 3.25 hours.
Explanation:
The time required to melt the frost dependes on the latent heat of the frost and the amount of heat it is transfered by convection to the air .
The heat transferred per unit area can be expressed as:
being hc the convective heat transfer coefficient (2 Wm^-2K^-1) and ΔT the difference of temperature (20-0=20 °C or K).
If we take 1 m^2 of ice, with 2 mm of thickness, we have this volume
The mass of the frost can be estimated as
Then, the amount of heat needed to melt this surface (1 m²) of frost is
The time needed to melt the frost can be calculated as
Explanation:
The electronic configuration of an atom can be represented by either sublevel notation or using shell notations.
Sublevel notations shows the sequence of filling electrons into the orbitals of the sublevels.
Shell notations are used to denote the electrons in all orbitals of each energy level.
Element Number of electrons Sub-level notation shell notation
Mg 12 1s² 2s² 2p⁶ 3s² 2 8 2