Data:
Molar Mass of NaOH = 40 g/mol
Solving: <span>According to the Law Avogradro, we have in 1 mole of a substance, 6.02x10²³ atoms/mol or molecules
</span>
1 mol -------------------- 6.02*10²³ molecules
y mol -------------------- 2.70*10²² molecules
6.02*10²³y = 0.270*10²³


Solving: <span>Find the mass value now
</span>
40 g ----------------- 1 mol of NaOH
x g ------------- 0.04 mol of NaOH


Answer:
The mass is 1.6 grams
To solve this problem, we use Beer's Law: A= ε.l.c
A is the absorbance- 0,558
<span>ε is</span> the molar absorptivity- is <span>15000 </span><span><span>L⋅mol-1</span><span>cm-1</span></span>
<span>l is </span>the length of the cuvette- 1 cm
<span>c is</span> the molar concentration
Applying the formula,
0,558= 15000 x 1 x c
0,558/15000= c
c= <span>3.72×<span>10⁻⁵ </span> <span>mol⋅L<span>⁻¹</span></span></span>
<span />
Answer:
Sodium
(Na)
Just count the electrons and search which atom it is.
Answer:
4.549 kg.
Explanation:
- We can use the general law of ideal gas: <em>PV = nRT.</em>
where, P is the pressure of the gas in atm (P = 2 x 10⁴ kPa/101.325 = 197.4 atm).
V is the volume of the gas in L (V = 20.0 L).
n is the no. of moles of the gas in mol (n = ??? mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of the gas in K (T = 23° C + 273 = 296 K).
<em>∴ n = PV/RT =</em> (197.4 atm)(20.0 L)/(0.0821 L.atm/mol.K)(296 K) = <em>162.5 mol.</em>
- To find the mass of N₂ in the cylinder, we can use the relation:
<em>mass of N₂ = (no. of moles of N₂)*(molar mass of N₂) = </em>(162.5 mol)*(28.0 g/mol) = <em>4549 g = 4.549 kg.</em>