<span>A characteristic feature of diatom cells is that they are encased within a unique cell wall made of silica (hydrated silicon dioxide) called a frustule.</span>
<u>Answer:</u> The molality of 
solution is 0.782 m
<u>Explanation:</u>
Molality is defined as the amount of solute expressed in the number of moles present per kilogram of solvent. The units of molarity are mol/kg. The formula used to calculate molality:
.....(1)
Given values:
Moles of = 0.395 mol
Mass of solvent (water) = 0.505 kg
Putting values in equation 1, we get:
Hence, the molality of solution is 0.782 m
The answer is A (The ability to react with oxygen)
An electron
proton=positive charge
electron=negative charge
Answer:
88.5 g/m is the molar mass for the gas
Explanation:
We need the Ideal Gases Law equation to solve this:
P . V = n . R . T
Pressure (P) = 10 Torr
We must convert to atm → 10 Torr / 760 Torr = 0.0131 atm
Volume (V) = 255 mL
We must convert to L → 255 mL / 1000 = 0.255 L
n = number of moles
moles = mass in g / molar mass
12.1 mg/ 1000 = 0.0121 g
T° = 25°C + 273K = 298K
R = 0.082 L.atm /mol.K
Let's replace the values
0.0131 atm . 0.255L = 0.0121 g / x . 0.082 L.atm /mol.K . 298K
(0.0131 atm . 0.255L) / (0.082 L.atm /mol.K . 298K) = 0.0121 g / x
1.367×10⁻⁴ /mol = 0.0121 g / x
x = 0.0121 g / 1.367×10⁻⁴ mol = 88.5 g/m
