Answer:
34.15% is the mass percentage of calcium in the limestone.
Explanation:
Mass of precipitate that is calcium oxalate = 140.2 mg = 0.1402 g
1 mg = 0.001 g
Moles of calcium oxalate = 
1 mole of calcium oxalate have 1 mole of calcium atom.
Then 0.001095 moles of calcium oxalate will have 0.001095 moles of calcium atom.
Mass of 0.001095 moles of calcium :
0.001095 mol × 40 g/mol = 0.04381 g
Mass of sample of limestone = 128.3 mg = 0.1283 g
Percentage of calcium in limestone:

34.15% is the mass percentage of calcium in the limestone.
When droplets of water in the atmosphere act like prism the color in the sunlight undergo interferance, making rainbows. ( This is how rainbows form)
<span>Kw = water autoionization constant=1.0 x 10-14 @ 25 °C
Kw = [H3O+] [OHÂŻ]
1.0 x 10-14= [x][x]
x=1.00 x 10ÂŻ7 M</span>
Answer:
https://prnt.sc/ql75rv
This is a link to an image of the lewis structure.
The answer is B a globe
Hope this helped