Why did mercuric oxide in Lavoisier’s reaction chamber weigh more thanthe mercury metal?

How does convection affect our atmosphere? our layers of earth? our oceans?

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid

Agirl throws a ball. if the ball's acceleration is 12 m/sec/sec and its mass is 0.5 kg, how much force did the girl apply to the ball?