Yes,this is an example:
An apple is sitting on a desk he is not in motion but one of the forces acting upon it is gravitational pull because is not floating around, the earth gravitational pull is pulling it down to the earth's surface.
Answer:
5.158 × 10²³ atoms K
General Formulas and Concepts:
<u>Chemistry - Atomic Structure</u>
- Reading a Periodic Table
- Using Dimensional Analysis
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
Explanation:
<u>Step 1: Define</u>
33.49 g K
<u>Step 2: Identify Conversions</u>
Avogadro's Number
Molar Mass of K - 39.10 g/mol
<u>Step 3: Convert</u>
<u />
= 5.15797 × 10²³ atoms K
<u>Step 4: Check</u>
<em>We are given 4 sig figs. Follow sig figs and round.</em>
5.15797 × 10²³ atoms K ≈ 5.158 × 10²³ atoms K
The complete question is as follows: Which statement describes the way in which energy moves between a system reacting substances in the surroundings.
A) molecule Collisions transfer thermal energy between the system and its surroundings
B) The thermal energy of the system and it’s surroundings increase
C) The potential energy of the system and it’s surroundings increases
D) molecular collisions create energy that is then released into the surroundings
Answer: The statement, molecule Collisions transfer thermal energy between the system and its surroundings describes the way in which energy moves between a system reacting substances in the surroundings.
Explanation:
When there will occur an increase in kinetic energy of molecules then there will occur more number of collisions.
When kinetic energy between these molecules tends to decrease then they will release heat energy into their surroundings.
As a result, it means that molecule collisions transfer thermal energy between the system and its surroundings.
Thus, we can conclude that the statement molecule Collisions transfer thermal energy between the system and its surroundings describes the way in which energy moves between a system reacting substances in the surroundings.
Answer:
12.6.
Explanation:
- We should calculate the no. of millimoles of KOH and HCl:
no. of millimoles of KOH = (MV)KOH = (0.183 M)(45.0 mL) = 8.235 mmol.
no. of millimoles of HCl = (MV)HCl = (0.145 M)(35.0 mL) = 5.075 mmol.
- It is clear that the no. of millimoles of KOH is higher than that of HCl:
So,
[OH⁻] = [(no. of millimoles of KOH) - (no. of millimoles of HCl)] / (V total) = (8.235 mmol - 5.075 mmol) / (80.0 mL) = 0.395 M.
∵ pOH = -log[OH⁻]
∴ pOH = -log(0.395 M) = 1.4.
∵ pH + pOH = 14.
∴ pH = 14 - pOH = 14 - 1.4 = 12.6.
Answer:
11.31g NaClO₂
Explanation:
<em> Is given 250mL of a 1.60M chlorous acid HClO2 solution. Ka is 1.110x10⁻². What mass of NaClO₂ should the student dissolve in the HClO2 solution to turn it into a buffer with pH =1.45? </em>
It is possible to answer this question using Henderson-Hasselbalch equation:
pH = pKa + log₁₀ [A⁻] / [HA]
<em>Where pKa is -log Ka = 1.9547; [A⁻] is the concentration of the conjugate base (NaClO₂), [HA] the concentration of the weak acid</em>
You can change the concentration of the substance if you write the moles of the substances:
[Moles HClO₂] = 250mL = 0.25L×(1.60mol /L) = <em>0.40 moles HClO₂</em>
Replacing in H-H expression, as the pH you want is 1.45:
1.45 = 1.9547 + log₁₀ [Moles NaClO₂] / [0.40 moles HClO₂]
-0.5047 = log₁₀ [Moles NaClO₂] / [0.40 moles HClO₂]
<em>0.3128 = </em>[Moles NaClO₂] / [0.40 moles HClO₂]
0.1251 = Moles NaClO₂
As molar mass of NaClO₂ is 90.44g/mol, mass of 0.1251 moles of NaClO₂ is:
0.1251 moles NaClO₂ ₓ (90.44g / mol) =
<h3>11.31g NaClO₂</h3>
