What is a physical change

Which two particles have opposite charges? (1) an electron and a neutron (2) an electron and a proton (3) a proton and a neutron (4) a proton and a positron

Sodium hydroxide dissolves in water according to the equation below. if the original temperature of the solution is 50°c, which might be the temperature after a period of time? naoh (s) → naoh (aq) δh = - 445.1 kj. mol

Is equal to the pressure of all the gases in the air above us at sea level?! O A. Atmosphere . O B. Millimeter of mercury . O C. Pascal • O D. Kelvin

In the formula CO2, what does the subscript 2 after the O mean

Carbon exists in nature as three isotopes. Given the atomic masses and relative abundance of the isotopes, what is the average atomic mass of carbon?

The heart is an example of which level of organization within an organism? O cell organ tissue organ system O O

NaOH+HCl--> NaCl+H2O what is the total number of grams of H2O produced when 116 grams of the product, NaCl, is formed?

Is a sample of liquid nitrogen more dense than a sample of nitrogen gas

You have a balloon containing 1 L of air at STP in a vacuum chamber. What will the volume of the balloon be when you reduce the pressure by half and increase the temperature to 373 K?

Which method will correctly determine whether the forces on an object are balanced or unbalanced? A. Multiply the forces in the horizontal direction by the forces in the vertical direction. B.