Question ( please help me ) 1 . Which diagram shows pure substance that are elements

2. Which diagram shows pure substance are compounds

3. Which diagram shows a mixture of compounds

4. Which diagram shows a mixture of elements

5. Which diagram shows a mixture of an element and a compound

How can one make a supersaturated solution? (apex)

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.

Ascientist measures the speed of sound in a monatomic gas to be 449 m/s at 20∘c. what is the molar mass of this gas?