Answer:
The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).
Explanation:
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Correct answer: "A. Energy from an outside source is continuously being added."
An endothermic reaction is a reaction that is characterised by the system absorbing energy from its surroundings. That energy is usually in heat form. For example, when mixing water<span> with potassium chloride, this reaction will absorb heat and the container will feel cold - endothermic reaction.</span>
The mass of 1.72 mol of magnesium fluoride is 107 grams.
To determine the mass of 1.72 mol of magnesium fluoride, we first need the chemical formula of magnesium fluoride. Magnesium forms a +2 ion (Mg+2) and fluoride forms a -1 ion (F-1). Since all compounds formed from ions have to be electrically neutral, we need 2 fluoride ions and 1 magnesium ion. Therefore, the formula for magnesium fluoride is MgF2.
Now we need to determine the molar mass of the compound from the molar mass values from the periodic table. Let's use a table to calculate this molar mass.
Molar mass of MgF2
Element Molar Mass (g/mol) Quantity Total (g/mol)
Mg 24.31 1 24.31
F 19.00 2 38.00
Total molar mass of MgF2 = 24.31 g/mol + 38.00 g/mol = 62.31 g/mol
This is the mass of one mole of the substance. If we have 1.72 mols of it, we multiply 1.72 by 62.31.
1.72 mol (62.31 g/mol) = 107 grams
We rounded to 107 to keep the correct number of significant digits in our answer.
Explanation:
Atoms never gain protons; they become positively charge only by losing electrons. A positive ion is called a cation (pronounced: CAT-eye-on). You may have notice that the number of neutrons in each of these ions was not specified.
