Answer:
6.46×10²² formula units
Explanation:
From the question given above, the following data were obtained:
Mass of MgCl₂ = 10.2 g
Number of formula units =?
From Avogadro's hypothesis,
1 mole of MgCl₂ = 6.02×10²³ formula units
But,
1 mole of MgCl₂ = 24 + (35.5×2) = 24 + 71 = 95 g
Thus, we can say:
95 g of MgCl₂ = 6.02×10²³ formula units
Finally, we shall determine the formula units in 10.2 g MgCl₂. This can be obtained as follow:
95 g of MgCl₂ = 6.02×10²³ formula units
Therefore,
10.2 g of MgCl₂ = (10.2 × 6.02×10²³) / 95
10.2 g of MgCl₂ = 6.46×10²² formula units
Thus, 10.2 g of MgCl₂ contains 6.46×10²² formula units
protons and electrons are both always the atomic number which is 9 in this case.
For neutrons you subtract the atomic number (9) from the weight of the atom (18.998) some teachers will want you to round to the nearest whole (19). We do this because the number of protons is the atomic number so if you subtract the protons from the whole weight of the atom you would have the electrons and neutrons left. Since electrons weigh so little we don't have to subtract them. Weighing neutrons and electrons would be like weighing an elephant (neutrons) and then putting one marshmallow on the scale (electron).
solid carbon dioxide, iodine, arsenic, and naphthalene
Explanation:
Examples of substances that undergo sublimation
Examples of solids that sublime are dry ice (solid carbon dioxide), iodine, arsenic, and naphthalene (the stuff mothballs are made of).
Answer:
62.98 % of the sample of hydrate is water
Explanation:
Step 1: Data given
Mass of the sample of a hydrate of sodium carbonate (Na2CO3) = 2.026 grams
After heating, the mass of the sample is 0.750 g
Molar mass H2O = 18.02 g/mol
Step 2: Calculate mass of water
Mass water = mass of hydrate - mass of sample after heating
Mass water = 2.026 grams - 0.750 grams
Mass water = 1.276 grams
Step 3: Calculate mass % percent of water
Mass % of water = (mass of water / total mass hydrate) * 100 %
Mass % of water = (1.276 grams / 2.026 grams) *100 %
Mass % of water = 62.98 %
62.98 % of the sample of hydrate is water
