<h3><u>Answer;</u></h3>
pH = 12.33
<h3><u>Explanation;</u></h3>
The equation of reaction is :
LiOH(aq) + HCl(aq) --> LiCl(aq) + H2O(l)
Reactants left after the titrant is added;
Total Moles LiOH;
= 0.035L LiOH × (0.2moles/L)
= 0.007moles of LiOH
Moles of HCl;
= 0.023L HCl × (0.25moles/L)
= 0.00575moles HCl is the limiting reagent
Reacting amount of moles of LiOH;
= 0.0575 moles HCl *(1mole LiOH/1moles HCl)
=0.00575 moles LiOH (reacted)
Moles of LiOH left;
= 0.007moles total - 0.00575moles that react
= .00125 moles of LiOH (left)
LiOH is a strong base, which means that it ionizes completely.
0.00125moles LiOH *(moles/0.058L) = 0.02155M of LiOH
LiOH(aq) --> Li+(aq) + OH-(aq)
[LiOH] = [OH-] = 0.02155 M
pOH = -log[OH-]
pOH = -log(0.02155)
pOH= 1.67
pH = 14 - pOH
pH = 14 - 1.67
pH = 12.33
Answer:
CH₂ ; 67.1 %
Explanation:
To determine the empirical formula we need to find what the mole ratio is in whole numbers of the atoms in the compound. To do that we will first need the atomic weights of C and H and then perform our calculation
Assume 100 grams of the compound.
# mol C = 85.7 g / 12.01 g/mol = 7.14 mol
# mol H = 14.3 g / 1.008 g/mol = 14.19 mol
The proportion is 14.9 mol H/ 7.14 mol C = 2 mol H/ 1 mol C
So the empirical formula is CH₂
For the second part we will need to first calculate the theoretical yield for the 12.03 g NaBH₄ reacted and then calculate the percent yield given the 0.295 g B₂H₆ produced.
We need to calculate the moles of NaBH₄ ( M.W = 37.83 g/mol )
1.203 g NaBH₄ / 37.83 g/mol = 0.0318 mol
Theoretical yield from balanced chemical equation:
0.0318 mol NaBH₄ x 1 mol B₂H₆ / mol NaBH₄ = 0.0159 mol B₂H₆
Theoretical mass yield B₂H₆ = 0.0159 mol x 27.66 g/ mol = 0.440 g
% yield = 0.295 g/ 0.440 g x 100 = 67.1 %
Answer:
V₂ = 1.92 L
Explanation:
Given data:
Initial volume = 0.500 L
Initial pressure =2911 mmHg (2911/760 = 3.83 atm)
Initial temperature = 0 °C (0 +273 = 273 K)
Final temperature = 273 K
Final volume = ?
Final pressure = 1 atm
Solution:
Formula:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
by putting values,
V₂ = P₁V₁ T₂/ T₁ P₂
V₂ = 3.83 atm × 0.500 L × 273 K / 273 K × 1 atm
V₂ = 522.795 atm .L. K / 273 K.atm
V₂ = 1.92 L
Velocity = 3.61 m/s
<h3>Further explanation</h3>
Given
mass of child = 35 kg
mass of sled = 5 kg
Kinetic energy = 260 J
Required
velocity
Solution
Energy because its motion is expressed as Kinetic energy (KE) which can be formulated as:
KE = 1/2.mv²
mass of object :
= mass child + mass sled
= 35 kg + 5 kg
= 40 kg
Input the value :
v²=KE : 1/2.m
v²= 260 : 1/2.40 kg
v²=13
v=3.61 m/s
The correct answer is option B. X-rays are the waves found in the electromagnetic spectrum at a wavelength of 1x10^-11 - 1x10^-8 m and frequencies of 3x10^16 to 3x10^19 Hz. These waves penetrate easily through certain materials which made them usefule in the field of medicine.
