Calcium sulfide, a very rare ionic salt present in meteorites, are believed to be synthesized directly in the outer space from monatomic calcium and sulfur, as shown in the equation below:   
How many grams of S is needed to react completely with 25 moles of Ca, using the equation?  

(a) Calcium and chlorine react to give calcium chloride in acombination reaction. Write and balance the equation. (Type youranswer using the format CO2 for CO2. Use the lowest possiblecoefficients.)

( ) Ca + ( ) ( ) ? ( ) ( )

(b) Heating decomposes Na2CO3 to sodium oxide and carbon dioxide.Write and balance the equation. Type your answer using the formatCO2 for CO2. Use the lowest possible coefficients.)

( ) Na2CO3 ? ( ) ( ) + ( ) CO2

(a) Calcium and chlorine react to give calcium chloride in acombination reaction. Write and balance the equation. (Type youranswer using the format CO2 for CO2. Use the lowest possiblecoefficients.)

______ Ca +_______, _______ ? ________,_________

(b) Heating decomposes Na2CO3 to sodium oxide and carbon dioxide.Write and balance the equation. Type your answer using the formatCO2 for CO2. Use the lowest possible coefficients.)

________ Na2CO3 ?______,_______ +_______ CO2