Answer:
- 6.38x10²² molecules C₆H₁₂O₆
Explanation:
First we <u>convert the given masses into moles</u>, using the <em>compounds' respective molar mass</em>:
- 64.7 g N₂ ÷ 28 g/mol = 2.31 mol N₂
- 83 g CCl₄ ÷ 153.82 g/mol = 0.540 mol CCl₄
- 19 g C₆H₁₂O₆ ÷ 180 g/mol = 0.106 mol C₆H₁₂O₆
Then we multiply each amount by <em>Avogadro's number</em>, to <u>calculate the number of molecules</u>:
- 2.31 mol N₂ * 6.023x10²³ molecules/mol = 1.39x10²⁴ molecules
- 0.540 mol CCl₄ * 6.023x10²³ molecules/mol = 3.25x10²³ molecules
- 0.106 mol C₆H₁₂O₆ * 6.023x10²³ molecules/mol = 6.38x10²² molecules
Answer:
3 × 10⁴ kJ
Explanation:
Step 1: Write the balanced thermochemical equation
C₃H₈(g) + 5 O₂(g) ⟶ 3 CO₂(g) + 4 H₂O(g) ΔH = -2220 kJ
Step 2: Calculate the moles corresponding to 865.9 g of H₂O
The molar mass of H₂O is 18.02 g/mol.
865.9 g × 1 mol/18.02 g = 48.05 mol
Step 3: Calculate the heat produced when 48.05 moles of H₂O are produced
According to the thermochemical equation, 2220 kJ of heat are evolved when 4 moles of H₂O are produced.
48.05 mol × 2220 kJ/4 mol = 2.667 × 10⁴ kJ ≈ 3 × 10⁴ kJ
Answer:
The correct statements that you must check are:
- The oxygen atom has a greater attraction for electrons than the hydrogen atom does (second statement).
- The electrons of the covalent bond are not shared equally between the hydrogen and oxygen atoms (fourth statement).
Explanation:
Electronegativity is the relative ability of an atom to pull the electrons in a covalent bond.
Hydrogen has an electronegativity of 2.20 and oxygen has 3.44. That means that oxygen attracts the electrons more strongly than hydrogen does (second statement).
As consequence, the electrons in the covalent bond H - O of water are not shared equally (fourth statement): the electron density will be higher around the O atoms.
Of course, this discards the statement telling that hydrogen atom attracts electrons much more strongly than the oxygen atom, and the statement telling that hydrogen and oxigen have same electronegativity.
Such difference in electron densities creates a dipole moment, so you discard the last statement (that the water dipole moment is equal to zero).
.150 = 3
20.20 = 4
25.00 = 4
If a 0 does not have a number or a period after it, it is not significant.
If the 0 is behind the decimal point, it is always significant.
Answer is in Word document below (x - <span>number of units of </span>lactic acid,<span>
</span>y - <span>number of units of </span><span>glycolic acid).</span>
PLGA is a copolymer of poly lactic acid (PLA) and poly glycolic acid (PGA). It is biocompatible and biodegradable copolymer.
