Answer:
Samira's model correctly demonstrates how the properties changed with the rearrangement of the atoms. However not all atoms are accounted for. There is a missing reactant.
Explanation:
Samira's model correctly demonstrated how the atoms in two compounds reacted to form two new products. However, the elements present in the reactants side should be the elements that make up the new products in the product side. But as the diagram shows, Sameera has mistakenly added a new element to one of her products which will be wrong.
Answer: 
Explanation:
If percentage are given then we are taking total mass is 100 grams.So, the mass of each element is equal to the percentage given.
Mass of Mg = 10.89 g
Mass of Cl = 31.77 g
Mass of O = 57.34 g
Step 1 : convert given masses into moles.
Moles of Mg=
Moles of Cl = 
Moles of O =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Mg = 
For Cl = 
For O= 
The ratio of Mg :Cl : O= 1 : 2 : 8
Hence the empirical formula is
I did this when I was younger
An example of a land form from magma is B. Lava Plateau.
A calorimeter experiment is a set-up that provides insulation so that no heat escapes to the surroundings and all energy can be accounted for. It can be done at either constant volume or constant pressure. So, the answer to this is knowing the mass of water, the specific heat which is an empirical data, and the change in temperature which can be measured using a thermometer. This experiment could measure the mass of an unknown substance added or the specific heat of the substance or the calorimeter. <em>The answer is D.</em>
