Ca3(PO4)2 is the correct formula.
Answer:- 0.134 seconds
Solution:- The speed is given as 
and the circumference is 24900 miles which is same as the distance light have to covered. It asks to calculate the time required to cover this distance by the light.
Unit conversion is needed from miles to meters since the speed is given in meters per second.
1 mile = 1609.34 meters
Thus, 
= 40072566 meters
Now, 
Rearranged for time, that gives: 
Inserting the values:
= 0.134 seconds
Hence, light would take 0.134 seconds to traverse the indicated distance. The answer without the unit is 0.134.
Response:
The specific heat of the alloy 
Clarification:
Weight of the alloy 
= 25 gm
Initial temperature 
= 100°c = 373 K
Weight of the water 
= 90 gm
Initial temperature of water 
= 25.32 °c = 298.32 K
Final temperature 
= 27.18 °c = 300.18 K
Using the energy balance equation,
Heat released by the alloy = Heat absorbed by the water
[[ - ] = 
( - )
25 × × ( 373 - 300.18 ) = 90 × 4.2 (300.18 - 298.32)
This gives us the specific heat of the alloy.
Response: Option A) The lattice energy rises as cations become smaller, as demonstrated by LiF and KF.
Clarification: It has been observed that the lattice energy is largely determined by two primary factors regarding ionic solids:
i) The ionic charges - An increase in the charge of the ions corresponds to an increase in lattice energy.
and
ii) The size or radius of the ions - As the ionic size grows, the lattice energy diminishes accordingly.
Therefore, in this context, the latter factor is evident. Thus, it can be concluded that as cation sizes decrease among ionic solids, the lattice energy increases.
An r-selected species has a significantly faster reproductive rate compared to K-selected species.
The focus of r-selected species is on quick maturation and reproduction. They are likely to breed during short periods when water supply is available, thus enhancing their survival chances.
Conversely, K-selected species prioritize nurturing their young and tend to reproduce later. Due to the longer maturation time before breeding, by the time K-selected species are ready, the water supply may be depleted, leading to lower survival odds.
Hope this clarifies!
If you have more questions, don’t hesitate to ask! Have a fantastic day!:)
~Collinjun0827, Junior Moderator
