Quartz has the formula SiO2
From the periodic table:
mass of oxygen = 16 grams
mass of silicon = 28.0855 grams
Mass of one mole of quarts = 28.0855 + 2(16) = 60.0855 grams
number of moles = mass / molar mass
number of moles = 1.6 / 60.0855 = 0.0266 moles
Each mole of quartz contains Avogadro's number of atoms.
Therefore:
number of atoms in 1.6 g = 1.6 x 6.02 x 10^23 = 1.603 x 10^22 atoms
A. Of a given element have different numbers of neutrons
A) Metal has luster
Metals are ductile, malleable, and good conductors of heat.
Answer: 
Explanation:
Depression in freezing point is given by:
= Depression in freezing point
i= vant hoff factor = 1 (for non electrolyte like urea)
= freezing point constant = 
m= molality
Weight of solvent (X)= 950 g = 0.95 kg
Molar mass of non electrolyte (urea) = 60.06 g/mol
Mass of non electrolyte (urea) added = ?
Thus urea was dissolved.
Moles of helium is required to blow up a balloon to 87.1 liters at 74 C and 3.5 atm is 021.65 mole
Mole is the unit of amount of substances of specified elementary entities
According to the ideal gas law he number of moles of a gas n can be calculated knowing the partial pressure of a gas p in a container with a volume V at an absolute temperature T from the equation
n =pV/RT
Here given data is volume = 87.1 liters
Temperature = 74 °C means 347.15 k
Pressure = 3.5 atm
R = 0.0821
Putting this value in ideal gas equation then
n =pV/RT
n = 3.5 atm×87.1 liters / 0.0821 ×347.15 k
n = 021.65 mole
Moles of helium is required to blow up a balloon to 87.1 liters at 74 C and 3.5 atm is 021.65 mole
Know more about mole of helium
brainly.com/question/23365554
#SPJ1
