Answer:
to study sub terranian earth movements
Explanation:
8H earth science
1.386 g of Mg ribbon combusts to form 2.309 g of oxide product. The mass percent of oxygen in the oxide is 40.0 %.
Let's consider the reaction for the combustion of Mg.
Mg + 1/2 O₂ ⇒ MgO
1.386 g of Mg combusts to form 2.309 g of MgO. We want to determine the mass of oxygen in MgO. According to Lavoisier's law of conservation of mass, matter is not created nor destroyed over the course of a chemical reaction. Then, the mass of Mg in the reactants is equal to the mass of Mg in MgO. The mass of the magnesium oxide is the sum of the masses of magnesium and oxygen. The <u>mass of oxygen in the oxide</u> is:

We can calculate the mass percent of O in MgO using the following expression.

You can learn more about mass percent here: brainly.com/question/14990953
Answer: Potential energy is converted to kinetic energy and back again.
Explanation:At points 1 and 3, the pendulum stops moving, and its mechanical energy is purely potential. At point 2, the pendulum is moving the fastest, and its mechanical energy is purely kinetic. Therefore, as the pendulum moves from point 1 to point 3, its potential energy is first converted to kinetic energy, then back to potential.
It is A I took it befor hope this helps:)
A chemical formula shows the kinds and numbers of <u>atoms</u> in the smallest representative unit of a substance.
<u>Explanation:</u>
In chemistry, a formula unit is the empirical formula of "ionic or covalent network solid compound" that is used as an independent entity for "stoichiometric calculations". This formula is a representation of a molecule that uses chemical symbols.
The unit is the lowest whole number ratio of ions represented in an ionic compound. It gives the numbers of atoms representing the "smallest representative" unit of a substance. The number of atoms also tells us about the chemical and physical properties of the compound formed.