When copper combines with oxygen, copper (ii) oxide is formed. if 7.0 mol of copper reacts with 4.0 mil of oxygen, what amount of the excess reactant remains?

I believe that there are .5 moles of O₂ left over.

Explanation: O₂+ 2 Cu= 2 CO₂+ 2 H₂O. With 7 moles of Cu you can get 7 moles of CuO. But, with 4 moles of O₂ you can get 8 moles of CuO, so O₂ is the limiting reactant. Thus, you would have to use 7 moles of Cu in order to determine the moles of O₂ and you get 3.5 moles of O₂. 4 moles- 3.5 moles =.5 moles

rosa was looking for patterns to predict the products of chemical reactions. she recorded three similar decomposition reactions in the table.she should record 2licl + 3o2.

in the last row of the table. it is the thermal decomposition of chlorate lithium, hence, she should record these products as: lithium chloride ( 2licl ) and oxygen ( 3o2 )   2 > 2 licl + 3o2.