Because flame provides a source of heat so that the magnesium metal atoms can overcome their activation energy. Activation energy is the minimum energy required in order for a chemical reaction to proceed. When the magnesium metal burns it reacts with oxygen found in the air to form Magnesium Oxide.
To determine the mass of the sample, first find the volume difference after and before the aluminum was placed, the volume change is equal to the volume of the submerged object, in this case aluminum.
Then knowing volume of aluminum and the density of it, we can solve for the mass.
D = m/v
Dv = m
2.7 g/ml • 8 ml = 21.6 grams.
Answer:

Explanation:
Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.
Answer:
Students have investigated what's going on in the fictional town of Westfield, they learned that the mysterious reddish-brown substance in the water is actually rust, which formed because of a chemical reaction between the iron pipes and the fertilizer substance in the water.
Explanation: