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Galina-37 [17]
3 years ago
15

PLEASE HELP!!!

Chemistry
2 answers:
Natalija [7]3 years ago
8 0

Answer:

aaaaaaaaaa bbbbbccccddddeeeffffggghhhhiiijjjkkkklllmmmnnnnooppppqqqqqrrrssstttuuuuvvvvvwwwwwyyyyxxxxxttttuuuuuuvvvvv

Explanation:

julsineya [31]3 years ago
7 0
A wet barometer puts a vacuum above a liquid and applies air pressure to the surface of the liquid - the height of the liquid above to reservoir surface is the measure of air pressure. The liquid can be in a J tube with an open end or a straight tube in a pool. Air pressure will support about 30" of mercury or about 32 feet of water. 
<span>A dry barometer uses a sealed chamber with a diaphragm with a lever touching it or a spiral tube with a link connected to a display needle. In the former, the slight movement of the diaphragm with changed pressure is translated to a large movement of the end of the lever movement across the scale. In the spiral, the expanding/contracting air inside the tube changes its shape and pulls the needle over. </span>
<span>In both case, the scale of pressure for the needle has to be calibrated to the design. </span>
<span>- </span>
<span>How Tropical Cyclones are Observed </span>
<span>* Direct measurements of tropical storm and hurricane dimensions and wind speeds are taken primarily by reconnaissance </span>
<span>aircraft, although ships and buoys also take important measurements. Once a hurricane is near and/or on land, Automated </span>
<span>Surface Observation Systems (ASOS) provide surface conditions, and radio sondes take upper air measurements. </span>
<span>* Indirect observational methods include satellite imagery and Doppler radar. In particular, satellites have greatly improved </span>
<span>our ability to monitor and understand hurricanes. Radar data are important once the storm comes close to shore </span>
<span>and after landfall for forecasting hurricane-related weather. </span>

<span>I hope this is helpful.</span>
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What are the two most common elements in the entire universe
g100num [7]

Answer: Hydrogen and Helium

Explanation: Hydrogen is made from from one proton and one electron, making them one of the simplest forms of elements in the universe. Combining hydrogen atoms creates helium, the second most common element in the Universe.

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3 years ago
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What types of chemical<br> reactions can change a toxic<br> chemical into one that is less<br> toxic
Masteriza [31]

Answer:

Very toxic materials are substances that may cause significant harm or even death to an individual if even very small amounts enter the body.There are a number of very toxic materials that may be used in workplaces. Some examples include carbon monoxide, hydrogen sulfide, chlorine and sodium cyanide

Explanation:

here are generally four types of toxic entities; chemical, biological, physical and radiation: Chemical toxicants include inorganic substances such as, lead, mercury, hydrofluoric acid, and chlorine gas, and organic compounds such as methyl alcohol, most medications, and toxins.

8 0
2 years ago
A chemistry student needs to standardize a fresh solution of sodium hydroxide. He carefully weighs out 28.mg of oxalic acid H2C2
Nezavi [6.7K]

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)

\frac{2}{1} =\frac{x}{2.52}\\ \\ \\x=0.000311(2)=0.000622

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.

5 0
3 years ago
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Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in aqueous solution. What should be the molarity of
dsp73
The first thing we need to do here is to recognize the unit of molarity and the units of the given percentage of nitric acid.

Molarity is mol HNO3 / L of solution. This is our aim

The given percentage is 0.68 g HNO3/ g solution

multiplying this with density to convert g solution into mL solution and dividing with the molecular weight of HNO3 (63 g/mol) to convert g HNO3 to mol. Therefore we obtain

0.016 mol/ mL or 16.23 mol/ L (M)

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Warm air lifted over a moving cold air mass will produce a front
crimeas [40]

Answer:

cold

Warm air lifted over a moving cold air mass will produce a _____ front.

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