Answer:
A). The complementary shapes of an enzyme and a substrate.
Explanation:
The Lock-and-key mechanism was proposed by Emil Fischer for the first time and characterized as the metaphor which helps in elucidating the specificity of the enzymatic reactions. In this metaphor, the lock is described as the enzyme while 'key' is characterized as the substrate which the enzyme acts upon. If the key is not appropriately sized, it will not fit into the active site i.e. the keyhole of the lock or enzyme and reaction will not take place. Thus, <u>option A</u> is the correct answer.
Answer:
Explanation:
Calcium chloride is a soluble salt which dissociates into calcium and chloride ions when dissolved in water.
CaCl₂(aq) ----> Ca²⁺(aq) + 2Cl⁻(aq)
Similarly, sodium oxalate when dissolved in water dissociates into sodium and oxalate ions.
Na₂CO₄(aq) ----> 2Na⁺(aq) + C₂O₄²⁻(aq)
However, in a double displacement reaction where the two solutions of the salts are mixed, the insoluble salt calcium oxalate is precipitated. The net ionic equation for the reaction is shown below:
Ca²⁺(aq) + C₂O₄²⁻(aq) ----> CaC₂O₄(s)
Answer:
Xenon
Explanation:
Step 1: Given data
- Pressure (P): 1.00 atm (I looked it up)
Step 2: Convert the temperature to Kelvin
K = °C + 273.15 = 100.0°C + 273.15 = 373.2 K
Step 3: Calculate the number of moles (n)
We will use the ideal gas equation.
P × V = n × R × T
n = P × V / R × T
n = 1.00 atm × 0.335 L / (0.0821 atm.L/mol.K) × 373.2 K
n = 0.0109 mol
Step 4: Calculate the molar mass of the gas
M = 1.44 g / 0.0109 mol = 132 g/mol
Step 5: Identify the gas
The gas with a molar mass of about 132 g/mol is xenon.
<span>Percentage
by mass is the amount in mass of a component in a mixture per 100 unit of mass of the
total mixture. Percentage by mass is the same as %w/w. We can determine this by dividing the mass of the solute with the total mass of the mixture. However, from the problem statement, we are given the volume of the water so there is a need to convert this value to mass by using the density of water. We calculate as follows:
Mass of solution = 100 mL (0.99993 g/mL) water + 25 g EtOH
Mass of solution = 124.993 g solution
%w/w = 25 g / 124.993 g x100
%w/w = 20% of EtOH</span>
Well ask yourself why don't we count it in moles and you should get your answer.