A 0.250 g sample of calcium metal is heated in a 38,500 g crucible in presence of excess of air. The resulting crucible and product weigh 38,850 g. What is the amount of oxygen interacted?
None of the above
0 0.250 g
O 0.350 g
O 0.100 g

The mass of a neutron is equal to the mass of a proton plus the mass of an electron. true or false false true

In pqr m< p=60 m< q= 30 and m

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.