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Ivan
2 years ago
7

an atom has 70 protons, 70 electrons, and 99 neutrons. what is the mass number? group of answer choices

Chemistry
1 answer:
Blizzard [7]2 years ago
6 0

Answer:

169

Explanation:

protons+neutrons=atomic mass

70+99=169

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A large flask is evacuated and weighed, filled with argon gas, and then reweighed. When reweighed, the flask is found to have ga
vivado [14]

Answer:

The molar mass of the unknown gas is 100.4 g/mol

Explanation:

Step 1: Data given

Molar mass of argon = 39.95 g/mol

After filling with argon the flask gained 3.221 grams

After filling with an unknown gas, the flask gained 8.107 grams

Step 2: Calculate the molar mass of the unknown gas

The gas with the higher molar mass will have the higher density.

Ar - 3.224 g; molar mass = 39.95 g/mol

X = 8.102 g; molar mass = ??

Molar mass of the unknown gas = 8.102g X *(39.95 g/mol  / 3.224 g) = 100.4 g/mol

The molar mass of the unknown gas is 100.4 g/mol

8 0
3 years ago
Which is an unnecessary rule for writing chemical formulas?
balandron [24]
The correct answer are

identify the positive ion and charge
balance the charges
identify the negative ion and charge
7 0
3 years ago
An element belonging to the halogen family would be expected to have a ________ ionization energy and a ________ electron affini
nikklg [1K]
<span>An element belonging to the halogen family would be expected to have a large ionization energy and a large electron affinity.
Flourine, Chlorine, Bromine, Iodine and astatine are the elements that belongs to the halogen family and mostly they have high values of ionization energy. 
The amount of energy released when an electron is added to an atom or molecule to form a negative ion or anion is electron affinity.</span>Chlorine from this family has highest electron affinity.

8 0
3 years ago
2.93 mol of MgF2 to grams
mojhsa [17]

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.

8 0
2 years ago
Why are some examples of a chemical reaction not actually foolproof evidence that of a chemical reaction?13, 8th grade, and I'm
kvasek [131]
So basically, the change in color effects the amount of cations in the solution making it a physical change rather than a chemical one, defying the law of conservation of mass! I hope this helped! (The only time the change in color affects the amount of cations is in the Alkaline Earth Metals)

source: college science teacher 
7 0
3 years ago
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