Cuál de las siguientes reacciones es de descomposición. CaCO3 > CaO + CO2
HCl + Zn → ZnCl2 + H2
H2SO4 + NaOH → NaSO4 + H2O
Fe + O2 → Fe2O3

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.

Asample of tin (ii) chloride has a mass of 0.49 g. after heating, it has a mass of 0.41 g.  what is the percent by mass of water in the hydrate?   %

Which statement explains which thermometer is more appropriate to measure the temperature of a liquid at 43.6 degrees celsius a) thermometer a, because it measures temperature more accurately than thermometer b b) thermometer b, because it measures temperature more accurately than thermometer a c) thermometer a, because it measures temperature more precisely than thermometer b d) thermometer b, because it measures temperature more precisely than thermometer a