If 832 joules of energy are required to raise the temperature of a sample of aluminum from 20.0 °C to 97.0 °C, and the specific heat of aluminum is 0.90 J/(g °C), what is the mass of the aluminum? 0.10 g Al
10.0 g Al
12.0 g Al
57.7 g Al

Three alkali metals in group 1 are a. calcium, strontium, barium b. boron, aluminum, gallium c. sodium, potassium, rubidium d. fluorine, iodine, chlorine

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.

Analyze the reaction to determine whether the reaction is exothermic or endothermic. explain your reasoning.