The time it took her to drive 2 km is 11.43 seconds, because sonverting kilometers to meters, it is 1000 meters to every kilometer, and she travels 2 kilometers, which is two-thousand meters. Then to find the time you need to divide the time by the speed, and with that you get 11.4285714286, or 11.43 seconds.
One separation technique to be used is the paper chromatography. This works by separating the components of the mixture through the difference of their concentrations. There is a stationary phase and the mobile phase, which flows through the stationary phase. The components travel at different rates and is usually signified by the colors. If more than one color would appear, that means that the dye is a mixture.
