What is the formula of the compound formed between the potassium ion and the sulfide ion?

The excretory system,need answers for all: )

What is the value of the standard enthalpy of formation of an element in its most stable form?

What are the advantages of using the metric system? designed as a decimal system making conversions simpler more accurate system of measurement has prefixes that correspond to an amount to use with all base units used by the entire scientific community