Which two elements most likely have the most similar properties?

beryllium and boron

scandium and silicon

nitrogen and phosphorus

hydrogen and helium

An oxide XO2 has a vapour density of 32. What is the atomic mass of X?

Five darts strike near the center of the target. Who ever threw the darks is?

Air water and the sun form

5) Determine the mass in grams of 4.82 moles of water molecules if the molar mass of water is 18.02 g/mol

Sponges can reproduce sexually and asexually, but avoid self-fertilization. What is an advantage of avoiding self-fertilization? Why would budding an exact clone be better?

There is a large increase in ionization energy between the second and the third ionization energies of a metal. What kind of ion is the metal likely to form? Include the charge in your answer.

Which of the following are true statements about equilibrium systems? For the following reaction at equilibrium: CaCO3 (s) ⇌ CaO (s) + CO2 (g) adding more CaCO3 will shift the equilibrium to the right.

How many sulfide ions are present in 23.5g of Sb2S3

2. An automobile tire has a pressure of 210 kPa at 293 K. What will be the tire pressure after driving, if the tire temperature rises to 308 K?

Students measuring the mass of a rock record 6.759 g, 6.786 g, 6.812 g, and 6.779 g. Which other measurement of the block's mass would be most precise? A. 6.702 g B. 6.781 g C. 6.605 g D. 6.858 g