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:
60.9 Kelvin
Explanation: First, write out everything that you know. You are tring to find the temperature, so the temperature will be represented by x.
Pressure (P)= 4.5 atm
Volume (V)= 3L
Number of Moles (n)= ?
Gas Consant (R)= 0.0821, if the pressure is in atm, that means r is 0.0821
Temperature (T)= x
We don't have all the information we need to plug the values into the equation. We still need to know how many moles 55.0 grans of neon is.
Ne in Grams= 55
Atomic Mass of Ne= 20.1797
55/20.1797= 2.7
moles= 2.7
Now that we have all the information we need, plug everying into the equation. In case you don't know, the Ideal Gas Law Equation is PV= nRT.
(4.5)(3) = (2.7)(0.821)x
x= 60.9
Now you have your temperature! It is 60.9 in Kelvin.
Answer:
The correct answer according to the uniformity the difference is whether you can distinguish more than one part in the mixture.
Explanation:
A homogeneous mixture is one in which with the naked eye or with a microscope no different parts can be distinguished. Its composition and properties are the same at all points, the substance is uniform.
In a heterogeneous mixture, we can observe different parts. Its composition is variable. It can be broken down into simpler substances by physical processes. The substance, in this case, is not uniform.
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