Here is the data a scientist collected from a sample of river water after filtering: The data support which of the following descriptions of the sample?
A.
It’s a mixture because dissolved ions in the water pass through the filter paper

B.
The substance is pure because the solid particles cannot pass through the filter paper

C.
It’s a mixture because solid particles are separated from the river water.

D.
It is a pure substance because the river water is composed of free elements

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.

An alloy contains 66 g of pure zinc. what is the percentage of zinc in the alloy? express your answer to two significant figures and include the appropriate units.

Suppose you increase your walking speed from 7 m/s to 15 m/s in a period of 1 s. what is your acceleration?