The gold leaf (not foil) is to give a sculpture or a painting appeal. Without it, it would discolour quicker.The gold leaf can be easily removed if needed to be.
57.0 is it rounded to three sig figs. You count three spaces then round from there, which would be the zero and you would round down because the four is there.
Physical change
Giddy Up!!!!!
Answer:
The relevant equation is:
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
Explanation:
1 mol of calcium carbonate can react to 2 moles of Hydrochloric acid to produce 1 mol of water, 1 mol of calcium chloride and 1 mol of carbon dioxide.
The formed CO₂ is the reason why you noticed bubbles as the reaction took place
The compound that was formed by the reaction of the first oxygen released by Cyanobacteria and iron are the metals of the earths crust. Cyanobacteria was the first organisms that used water instead of hydrogen sulfide or other compounds as a source of electrons and hydrogen for fixing carbon dioxide. Early Cyanobacteria inhabited marine sediments where Archean banded iron formations were deposited; consisting of reddish layers rich in iron oxide.
