How many formula units in 0.75 mol of KNO3?* 75.8 formula units 1.25E-24 formula units
4.5E23 formula units
22 2.3E25 formula units​

Following are the  advantages of the parametric equations: 1) they can be used to graph curves that are not functions, like the unit circle.2) the parameter can be used to represent the quantity that is  useful to  provide us with better information about the graph.3)  it is useful to convert between rectangular equations and parametric equations.with specific reference to chemistry,  parametric equations are employ for solving hydrogen and hydrogen-like ions, quantum mechanically. herein, cartesian coordinates are converted in spherical polar coordinates. the solution obtained, when plotted on spherical polar graph paper, provides visualization of atomic orbital such as s,p,d and f. 

Pretty sure it's d. heterogeneous is separated by physical properties. 

The surface of the water droplet is held together by the attraction between molecules. in order for water to flow more easily into these small spaces, you need to decrease its surface tension. you can do this by adding soap, which is a surfactant (a material that decreases the surface tension of a liquid).