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2 years ago

A basketball player jumps straight up to dunk a basketball. The basketball player's speed increases as she returns to the

Chemistry

1 answer:

katen-ka-za [31]2 years ago

7 0

Options :

The upward force is greater than the downward force.

The downward force is greater than the upward force.

The rightward force is greater than the leftward force.

The leftward force is greater than the rightward force.

Answer:

The downward force is greater than the upward force.

Explanation:

When the player jumps to dunk a basket ball, it requires an upward force exerted on the person due to the push by the person to jump, after dunking the basket ball, the player attains maximum height, where his final velocity becomes zero and his direction changes (from upward to downward), at this point his velocity increases due to the additional force exerted on the player due to the Earth's Gravitational pull - which is a downward force which acts on an object).

Hence, it could be concluded that the increase in speed of the basketball player as she returns to the ground means that the downward force is greater than the upward force acting on the player.

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A 118-ml flask is evacuated and found to have a mass of 97.129 g. when the flask is filled with 768 torr of helium gas at 35 ?c,

Inessa05 [86]

The full question asks to decide whether the gas was a specific gas. That part is missing in your question. You need to decide whether the gas in the flask is pure helium.

To decide it you can find the molar mass of the gas in the flask, using the ideal gas equation pV = nRT, and then compare with the molar mass of the He.

From pV = nRT you can find n, after that using the mass of gass in the flask you use MM = mass/moles.

1) From pV = nRT, n = pV / RT

Data:
V = 118 ml = 0.118 liter
R = 0.082 atm*liter/mol*K
p = 768 torr * 1 atm / 760 torr = 1.0105 atm
T = 35 + 273.15 = 308.15 K

n = 1.015 atm * 0.118 liter / [ 0.082 atm*liter/K*mol * 308.15K] =0.00472 mol

mass of gas = mass of the fask with the gas - mass of the flasl evacuated = 97.171 g - 97.129 g = 0.042

=> MM = mass/n = 0.042 / 0.00472 = 8.90 g/mol

Now from a periodic table or a table you get that the molar mass of He is 4g/mol

So the numbers say that this gas is not pure helium , because its molar mass is more than double of the molar mass of helium gas.

7 0

3 years ago

46. True or false. Chemical reactions do not involve changes in the chemical bonds that join

Naddika [18.5K]

Answer:

Chemical reactions do not involve changes in the chemical bonds that join

atoms in compounds :

False

Explanation:

Chemical reaction are the reaction in which old bonds break and new bonds are formed . The formation of new bond result in formation of new compounds . This happen because new bond are result of linking different atoms by the bond.

For example : Water formation from Oxygen and Hydrogen is a chemical process :

$2H_{2}+O_{2}\rightarrow 2H_{2}O$

Original(old) bonds are :

H-H bond in H2 and O-O bonds in O2

In H2 = Hydrogen is joined to Hydrogen

IN O2 = Oxygen is joined to oxygen

New Bonds =

O-H bonds in water (H2O)

Oxygen is joined to hydrogen = New Bond formation

Hence,

Chemical reactions do involve changes in the chemical bonds that join

atoms in compounds

3 0

3 years ago

The state of matter in which molecules are attracted to each other but can change position is a

slavikrds [6]

i believe the answer is a liquid

4 0

3 years ago

Which substance has Hf defined as 0 kJ/mol? H2O (s) Ne (l) O2 (g) CO2 (g)

vlabodo [156]

Answer:

O₂ (g).

Explanation:

All elements that found in nature has heat of formation (Hf) equal 0 J/mol.

So, the substance that has heat of formation (Hf) equal 0 J/mol is O₂ (g).

H₂O is formed from the reaction of hydrogen and oxygen and has Hf, Also, the solidification of H₂O (s) from H₂O (l) has (Hf).

Although, Ne (g) is found in nature and has no Hf, the liquification to form Ne (l) has heat of formation (Hf).

CO₂ (g) is formed from the reaction between carbon and oxygen and so has heat of formation (Hf).

8 0

3 years ago

Read 2 more answers

1.34 milligrams is the same as _____ kg and _____g.

Karolina [17]

Answer C is for kg and but it's .00134 for grams

3 0

3 years ago

Read 2 more answers