Answer:
speed=5cm/minute
Explanation:
Given at 2:00PM the hermit is at 10cm mark
Also given that the hermit reaches 60cm mark at 2:10PM
Therefore the time elapsed is 10 minutes = 
the distance travelled by the hermit is 60-10=50cm=0.5m
We know that
speed = 
m/sec=5cm/minute
Answer:
- The molarity of the student's sodium hydroxide solution is 0.0219 M
Explanation:
<u>1) Chemical reaction.</u>
a) Kind of reaction: neutralization
b) General form: acid + base → salt + water
c) Word equation:
- sodium hydroxide + oxalic acid → sodium oxalate + water
d) Chemical equation:
- NaOH + H₂C₂O₄ → Na₂C₂O₄ + H₂O
b) Balanced chemical equation:
- 2NaOH + H₂C₂O₄ → Na₂C₂O₄ + 2H₂O
<u>2) Mole ratio</u>
- 2mol Na OH : 1 mol H₂C₂O₄ :1 mol Na₂C₂O₄ : 2 mol H₂O
<u>3) Starting amount of oxalic acid</u>
- mass = 28 mg = 0.028 g
- molar mass = 90.03 g/mol
- Convert mass in grams to number of moles, n:
n = mass in grams / molar mass = 0.028 g / 90.03 g/mol = 0.000311 mol
<u>4) Titration</u>
- Volume of base: 28.4 mL = 0.0248 liter
- Concentration of base: x (unknwon)
- Number of moles of acid: 2.52 mol (calculated above)
- Proportion using the theoretical mole ratio (2mol Na OH : 1 mol H₂C₂O₄)
That means that there are 0.000622 moles of NaOH (solute)
<u>5) Molarity of NaOH solution</u>
- M = n / V (liter) = 0.000622 mol / 0.0284 liter = 0.0219 M
That is the correct number using <em>three signficant figures</em>, such as the starting data are reported.
A molecule that has a central atom surrounded by three single bond pairs and one unshared pair would have a trigonal pyramidal shape. The electon arrangement of this is called tetrahedral. It involves one atom located at the apex and at the corners are three atoms with a trigonal base. An example would be ammonia or NH3. Nitrogen has five valence electrons so that it needs to three more electrons to satisfy the octet rule and be stable. It would share electrons with the three nitrogen present. In order, to achieve the most stable geometry, the three atoms of hydrogen would attach with a bond angle of 109 degrees.
Answer:Switch off lighting in refrigeration areas when not in use?
Explanation:
