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goldfiish [28.3K]
4 years ago
15

How was it first discovered that hot air could rise?

Chemistry
1 answer:
Sunny_sXe [5.5K]4 years ago
6 0
The history of balloon flight dates to 1783, when two French brothers, Joseph and Etienne Montgolfier, discovered that filling a bag with hot air would cause it to rise. They demonstrated their principle at Annonay, France, on June 4, 1783, with an unmanned balloon made of linen and pape
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Which of these did you include in your response?
Natalka [10]

Answer:

Check all of them

Explanation:

All are correct.

- stong electrolytes dissolve completely

- weak disolve partially

- nonelectrolytes do not dissolve

7 0
4 years ago
• Define and describe in detail (and in your own words) ultrasound and infrasound
qaws [65]

Answer:

Human ears can hear sound waves that vibrate in the range from about 20 times a second (a deep rumbling noise) to about 20,000 times a second (a high-pitched whistling). (Children can generally hear higher-pitched sounds than their parents, because our ability to hear high frequencies gets worse as we get older.) Speaking more scientifically, we could say that the sounds we can perceive have a frequency ranging from 20–20,000 hertz (Hz). A hertz is a measurement of how often something vibrates and 1 Hz is equal to one vibration each second. The human voice makes sounds ranging from a few hundred hertz to a few thousand hertz.

Suppose you could somehow hit a drum-skin so often that it vibrated more than 20,000 times per second. You might be able to see the skin vibrating (just), but you certainly couldn't hear it. No matter how hard you hit the drum, you wouldn't hear a sound. The drum would still be transmitting sound waves, but your ears wouldn't be able to recognize them. Bats, dogs, dolphins, and moths might well hear them, however. Sounds this like, with frequencies beyond the range of human hearing, are examples of ultrasound.

Infrasonics, vibrational or stress waves in elastic media, having a frequency below those of sound waves that can be detected by the human ear—i.e., below 20 hertz. The range of frequencies extends down to geologic vibrations that complete one cycle in 100 seconds or longer.

4 0
3 years ago
Magnesium (used in the manufacture of light alloys) reacts with iron(III) chloride to form magnesium chloride and iron. 3Mg(s) +
Paladinen [302]

Answer:

Theanswer to your question is:

Limiting reactant = FeCl₃

Excess reactant = 1.66 g of Mg

Explanation:

Data

Mg = 41 g   = 24.31 g/mol

FeCl₃ = 175 g = 162.2 g/mol

                         3Mg(s) + 2FeCl₃(s) → 3MgCl₂(s) + 2Fe(s)

                      3(24.31) of Mg ------------------  2(162.2)  of FeCl₃

                      72.93 g of Mg ------------------ 324.4 g of FeCl₃

Theoretical Proportion = 324.4/72.93 = 4.44

Practical proportion   =  175 / 41 = 4.2

As the proportion disminishes the limiting reactant is FeCl₃.

Excess reactant

                               72.93 g of Mg ------------------ 324.4 g of FeCl₃

                                   x -------------------------           175 g of FeCl₃

x = (175 x 72.93) / 324.4

x = 39.34 g of Mg

Excess = 41 - 39.34

           = 1.66 g of Mg

4 0
3 years ago
Why doesn’t silicone (IV) oxide conduct electricity
choli [55]

Answer:

answer it by yourself and own way

4 0
3 years ago
As a part of a clinical study, a pharmacist is asked to prepare a modification of a standard 22g package of a 2% mupirocin ointm
Vesna [10]

Answer:

226.8 mg of mupirocin powder are required

Explanation:

Given that;

weight of standard pack = 22 g

mupirocin by weight = 2%

so weight of mupirocin = 2% × 22 = 2/100 × 22 = 0.44 g

so by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment

mg of mupirocin powder are required = ?, lets rep this with x

Total weight of ointment = 22 + x g

Amount of mupirocin  = 0.44 + x g

percentage of mupirocin  in ointment is 3?

so

3/100 = 0.44 + x g / 22 + x g

3( 22 + x g ) = 100( 0.44 + x g )

66 + 3x g = 44 + 100x g

66 - 44 = 100x g - 3x g

97 x g = 22

x g = 22 / 97

x g = 0.2268 g

we know that; 1 gram = 1000 Milligram

so 0.2268 g = x mg

x mg = 0.2268 × 1000

x mg  = 226.8 mg

Therefore, 226.8 mg of mupirocin powder are required

8 0
3 years ago
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