Planets look like bright stars when they are viewed from Earth.

If 100. mL of 0.400 M Na2SO4 is added to 200. mL of 0.600 M NaCl, what is the concentration of Na + ions in the final solution? Assume that the volumes are additive.

The ionization energy is the energy needed to remove an electron from an atom. In the bohr model of the hydrogen atom, this means exciting the electron to the n = ∞ state.

Determine the mass of 8.59 * 1023 atoms cl. answer in units of g.

The energy diagram shown represents the chemical reaction between solid ammonium chloride and solid barium hydroxide octahydrate: 2NH4Cl (s) + Ba (OH) 2⋅8H2O (s) →2NH3 (aq) + BaCl2 (aq) + 10H2O (l) The ΔH for this reaction is 54.8 kJ.

Significant digits are the number of digits that reflect the precision of a measurement or number. true or false

56 Explain, in terms of atomic structure, why the elements in Group 2 have similar chemical properties. 131

What must molecules do to react? a. Molecules must heat up b. Molecules must collide c. Molecules must expand to fill their container d. Molecules must interact with a catalyst

How many pictograms are in a gram?

Which type of signaling pathway uses second messengers because the hormone cannot pass through the plasma membrane? a.) amino acid based b.) lipid based

Why are the gases in the troposphere layer denser than the gases in the other layers?