Melting ice cream is a physical change because it is a phase change, the water in the ice cream gains thermal energy and the inter-molecular forces are overcome and the molecules move further apart forming a liquid. It is not a chemical change because no chemical reactions occurred.
Answer:
24.9 L Ar
General Formulas and Concepts:
<u>Atomic Structure</u>
- Reading a Periodic Table
- Moles
- STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K
<u>Aqueous Solutions</u>
<u>Stoichiometry</u>
- Using Dimensional Analysis
Explanation:
<u>Step 1: Define</u>
[Given] 40.0 g Ar
[Solve] L Ar
<u>Step 2: Identify Conversions</u>
[PT] Molar Mass of Ar - 39.95 g/mol
[STP] 22.4 L = 1 mol
<u>Step 3: Convert</u>
- [DA] Set up:
- [DA] Divide/Multiply [Cancel out units]:
<u>Step 4: Check</u>
<em>Follow sig fig rules and round. We are given 3 sig figs.</em>
24.9235 L Ar ≈ 24.9 L Ar
Answer:
5.6 seconds
Explanation:
The reaction follows a zero-order in dinitrogen monoxide
Rate = k[N20]^0 = change in concentration/time
[N20]^0 = 1
Time = change in concentration of N2O/k
Initial number of moles of N2O = 300 mmol = 300/1000 = 0.3 mol
Initial concentration = moles/volume = 0.3/4 = 0.075
Number of moles after t seconds = 150 mmol = 150/1000 = 0.15 mol
Concentration after t seconds = 0.15/4 = 0.0375 M
Change in concentration of N2O = 0.075 - 0.0375 = 0.0375 M
k = 0.0067 M/s
Time = 0.0375/0.0067 = 5.6 s
I believe the answer is C: "<span>It occurs when a hydrogen atom bonds with electropositive atoms."</span>
The bonds found between water molecules are called:
Hydrogen bonds
which contribute to water having a high number of Van Der Waals forces.
Explanation:
A hydrogen bond is an electromagnetic attraction within polar molecules in which hydrogen is joined to a larger atom, such as oxygen or nitrogen. This is not a dividing of electrons, as in a covalent bond. Preferably, this is an attraction among the positive and negative poles of charged atoms.
