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3 years ago

13

the tip of a match contains chemical energy. Kevin's father lit a match and blew out the flame. then he tried to light the same

match again . Kevin observed that nothing happened. what can you infer from this observation?

1 answer:

Ostrovityanka [42]3 years ago

8 0

The chemicals were used so it did not light again

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Which of the following is true for compounds?

soldi70 [24.7K]

Compound are formed by two or more elements chemically combined. For example: H^2O is the water formula, this is a compound because you two elements which are Hydrogen and Oxygen and together they form a compound. The (^2) is the amount of atoms the formula has, in this case Hydrogen has two atoms and Oxygen is neutral.

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3 years ago

How many moles of Boron (B) are in 5.03 x 1024 B atoms?

goldfiish [28.3K]

Hey there!:

Number of moles = ( number of atoms / 6.023*10²³ atoms )

given number of atoms = 5.03*10²⁴

Therefore:

Number of moles B = 5.03*10²⁴ / 6.023*10²³

Number of moles B = 8.35 moles

Hope that helps!

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2 years ago

When the temperature of the air is 25°C, the velocity of a sound wave traveling through the air is approximately

Vitek1552 [10]

Answer ; The correct answer is : 346 m/s .

Sound is a type of longitudinal wave , which is produced when a matter compress or refracts .

Speed of sounds depends on factors like medium , density , temperature etc .

Effect of Temperature on speed of sounds :

When the temperature increases , molecules gains energy and they starts vibrating and with higher temperature vibration becomes fast . So the waves of sounds can travel faster due to faster vibrations . Hence , speed of sounds is directly proportional to the temperature or speed of sounds increases with increase in temperature .

The speed of sounds at 0⁰C is 331 $\frac{m}{s}$

The relation between speed of sound and temperature is given as :

$V = 331 \frac{m}{s} + ( 0.6 \frac{m}{s- ^0C} * T )$

Given : Temperature = 25 ⁰ C

Plugging values in formula =>

$V = 331 \frac{m}{s} + (0.6 \frac{m}{s-^0C} * 25^0C)$

$V = 331 \frac{m}{s} + 15 \frac{m}{s}$

$V = 346 \frac{m}{s}$

7 0

2 years ago

What type of spectrum is produced when electromagnetic radiation is emitted or absorbed as electrons change energy levels in an

Setler79 [48]

Then as the electrons in the atoms fall back down, they emit electromagnetic radiation (light). The amount of light emitted at different wavelengths, called the emission spectrum, is shown for a discharge tube filled with hydrogen gas in Figure 12.6 below.

8 0

2 years ago

Read 2 more answers

A sample of PCl5(g) was placed in an otherwise empty flask at an initial pressure of 0.500 atm and a temperature above 500 K. Ov

tia_tia [17]

Answer:

Kp = 0.81666

Explanation:

Pressure of PCl₅ = 0.500 atm

Considering the ICE table for the equilibrium as:

PCl₅ (g) ⇔ PCl₃ (g) + Cl₂ (g)

t = o 0.500

t = eq -x x x

--------------------------------------------- --------------------------

Moles at eq: 0.500-x x x

Given the pressure of PCl₅ at equilibrium = 0.150 atm

Thus, 0.500 - x = 0.150

x = 0.350 atm

The expression for the equilibrium constant is:

$K_p=\frac {P_{PCl_3}P_{[Cl_2}}{P_{PCl_5}}$

So,

$K_p=\frac{x^2}{0.500-x}$

x = 0.350 atm

Thus,

$K_p=\frac{{0.350}^2}{0.500-0.350}$

<u>Thus, Kp = 0.81666</u>

7 0

3 years ago