Why are noontime shadows longer in winter than in summer?

Same as my last question this is astronomy not chemistry.

most elements have several stables but some such as lithium, boron, and copper have 2. Consider one such element (it doesn't matter which one). If the abundance of one isotope is 0.1266 what is the abundance of the other isotope?

How do I balance chemical equations?

If atoms are made of smaller parts such as electrons, why are atoms considered the basic unit of matter?

If i have 15.7g of sulfur, how do i work out how much iron is needed to make iron sulfide

17. kg into g convert following

There is inverse relation between pressure and diffusion in liquid phase? •True •False

What do you need in order to do a stoichiometric calculation? (Choose multiple) Balanced Chemical Equation Molar masses of compounds involved The type of reaction taking place Oxidation Numbers

The correct mathematical expression for finding the molar solubility (s) of sn (oh) 2 is:

18. which bond is most polar? H--F H--Cl H--Br H--I

What kind of reaction is ca (s) + h3po4 (aq) ca3 (po4) 2 (s) + h2 (g)