Answer:
<h2><em>please</em><em> </em><em>mark</em><em> </em><em>me</em><em> </em><em>brainliest</em></h2>
Explanation:
<h2>Packing fraction is defined as a way of expressing the variation of isotopic mass from whole mass number (atomic mass). This fraction can have positive or can have negative sign. A positive packing fraction describes a tendency towards instability.</h2><h2>The equation for packing fraction is: Packing fraction = (N atoms) x (V atom) / V unit cell. N atoms is the number of atoms in a unit cell. V atom is the volume of the atom, and V unit cell is the volume of a unit cell. Substitute the number of atoms per unit cell into the equation.</h2>
<span>83.9%
First, determine the molar masses of Al(C6H5)3 and C6H6. Start by looking up the atomic weights of the involved elements.
Atomic weight aluminum = 26.981539
Atomic weight carbon = 12.0107
Atomic weight hydrogen = 1.00794
Molar mass Al(C6H5)3 = 26.981539 + 18 * 12.0107 + 15 * 1.00794 = 258.293239 g/mol
Molar mass C6H6 = 6 * 12.0107 + 6 * 1.00794 = 78.11184 g/mol
Now determine how many moles of C6H6 was produced
Moles C6H6 = 0.951 g / 78.11184 g/mol = 0.012174851 mol
Looking at the balanced equation, it indicates that 1 mole of Al(C6H5)3 is required for every 3 moles of C6H6 produced. So given the number of moles of C6H6 you have, determine the number of moles of Al(C6H5)3 that was required.
0.012174851 mol / 3 = 0.004058284 mol
Then multiply by the molar mass to get the number of grams that was originally present.
0.004058284 mol * 258.293239 g/mol = 1.048227218 g
Finally, the weight percent is simply the mass of the reactant divided by the total mass of the sample. So
1.048227218 g / 1.25 g = 0.838581775 = 83.8581775%
And of course, round to 3 significant digits, giving 83.9%</span>
Answer : The percent by mass of water the salt contain is, 55.3 %
Explanation : Given,
Mass of hydrated salt = 12.10 g
Mass of salt = 5.41 g
First we have to calculate the mass of water.
Mass of water = Mass of hydrate salt - Mass of salt
Mass of water = 12.10 g - 5.41 g
Mass of water = 6.69 g
Now we have to calculate the percent by mass of water the salt contain.
Now put all the given values in this expression, we get:
Therefore, the percent by mass of water the salt contain is, 55.3 %
Answer:
Its a chemical change.
Explanation:
When baking soda and vinegar are mixed bubbles formed and new product is formed by both reactant. So its a chemical change because in a chemical change new substances are formed.
Chemical change:
The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.
These changes are irreversible
These changes occur due to chemical reactions
These may not be observed with naked eye
Example:
Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood
Boiling of egg: that change the chemical composition of protein in the egg .
The reaction of Hydrogen and oxygen:
H 2 (g) + O 2 (g) -------------------------------------> 2H 2O (l)
