Who recognized that elements properties repeated at regular intervals

Which statement describes a chemical reaction at equilibrium? (1) The products are completely consumed in the reaction. (2) The reactants are completely consumed in the reaction. (3) The concentrations of the products and reactants are equal.

A reproductive cell goes through interphase before beginning blank 1, but not before blank 2

The energy required for self-diffusion is 1.6eV. At 100 degrees C, 1% of the atoms have the energy required for self-diffusion. How many of the atoms would have the energy required for self-diffusion at 120 degrees C?

What is the mass of 18.8 moles of helium (He) atoms? 0.213 g 4.70 g 37.6 g 75.2 g

Which of the following factors can be changed for a gas without changing the mass of the gas? Select all that apply. volume temperature density number of particles pressure

Iron metal has a specific heat of 0.449J/g°C. How much heat is transferred to a 5.00 a piece of iron, initially at 20.0°C, when it is placed in a beaker of boiling water at 1 atm? Use Q = mcAt formula For chemistry

Which type of change occurs when the electrons of two atoms interact to form an atomic bond?

Which of the following is considered electronically perfect? a) Potassium b) Magnesium c) Argon d) Chlorine

The area of the circular base of a can of dog food is 12.5 in. The can is 6 inches high. What is its volume?

What is the tested variable in the experiment?