Compounds are substances in which two or more atoms are chemically combined to form a new, pure substance. Which of the following substances is NOT a compound
If you can please help with both if you can

Determine the change in width a, height b, thickness t when a plate is subjected to the uniform distributed load and is made of material having modulus of elasticity e=230 gpa and poisson's ratio ν=1/3. given : a=400 mm and b= 300 mm also the uniformly distributed load in downward y direction of plate is 2 mn/m and in the positive x direction is 3 mn/m and t=20 mm

Ryan is examining the energy of the particles in a bar of gold. what is ryan most likely studying?

Acid precipitation chemically weathering a 5.0-kg limestone rock . which coukd be the result ?