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4 years ago

Name one object that would be considered a solid. Describe how the atoms move in a solid object.

Chemistry

1 answer:

Vadim26 [7]4 years ago

4 0

Answer: solid base is like a chair a ice cube or a rock and your head

Explanation: plz let me let me know if you got it right in plz rate me the most brainlest

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If the mass of 3 black beans it's 0.7 what's the mass of one bean?

mamaluj [8]

Answer:0.233333333

Explanation: Let me be!

3 0

3 years ago

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Pentaborane-9, B5H9, is a colorless, highly reactive liquid that will burst into flame when exposed to oxygen. The reaction is 2

mina [271]

<u>Answer:</u> The amount of energy released per gram of $B_5H_9$ is -71.92 kJ

<u>Explanation:</u>

For the given chemical reaction:

$2B_5H_9(l)+12O_2(g)\rightarrow 5B_2O_3(s)+9H_2O(l)$

The equation used to calculate enthalpy change is of a reaction is:

$\Delta H^o_{rxn}=\sum [n\times \Delta H^o_f_{(product)}]-\sum [n\times \Delta H^o_f_{(reactant)}]$

The equation for the enthalpy change of the above reaction is:

$\Delta H^o_{rxn}=[(5\times \Delta H^o_f_{(B_2O_3(s))})+(9\times \Delta H^o_f_{(H_2O(l))})]-[(2\times \Delta H^o_f_{(B_5H_9(l))})+(12\times \Delta H^o_f_{(O_2(g))})]$

Taking the standard enthalpy of formation:

$\Delta H^o_f_{(B_2O_3(s))}=-1271.94kJ/mol\\\Delta H^o_f_{(H_2O(l))}=-285.83kJ/mol\\\Delta H^o_f_{(B_5H_9(l))}=73.2kJ/mol\\\Delta H^o_f_{(O_2(g))}=0kJ/mol$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(5\times (1271.94))+(9\times (-285.83))]-[(2\times (73.2))+(12\times (0))]\\\\\Delta H^o_{rxn}=-9078.57kJ$

We know that:

Molar mass of pentaborane -9 = 63.12 g/mol

By Stoichiometry of the reaction:

If 2 moles of $B_5H_9$ produces -9078.57 kJ of energy.

Or,

If $(2\times 63.12)g$ of $B_5H_9$ produces -9078.57 kJ of energy

Then, 1 gram of $B_5H_9$ will produce = $\frac{-9078.57kJ}{(2\times 63.12)}\times 1g=-71.92kJ$ of energy.

Hence, the amount of energy released per gram of $B_5H_9$ is -71.92 kJ

8 0

3 years ago

The air pressure in a tire is 2.38 atm. What is the pressure in kilopascals.

Anna71 [15]

Answer:

The answer is

Explanation:

To find the pressure in kilopascals we must first find the pressure in Pascal

To find the pressure in Pascal we use the conversion

1 atm = 101 , 325 Pa

If 1 atm = 101325 Pa

then 2.38 atm = 2.38 × 101325

= 241153.5 Pa

Converting it into kPa we have the final answer as

Hope this helps you

8 0

3 years ago

When a 0.235-g sample of benzoic acid is combusted in a bomb calorimeter, the temperature rises 1.643 ∘C . When a 0.275-g sample

andrew-mc [135]

Answer : The heat of combustion per mole of caffeine at constant volume is 76197.18 kJ/mole

Explanation :

First we have to calculate the specific heat calorimeter.

Formula used :

$Q=m\times c\times \Delta T$

where,

Q = heat of combustion of benzoic acid = 26.38 kJ/g = 26380 J/g

m = mass of benzoic acid = 0.235 g

c = specific heat of calorimeter = ?

$\Delta T$ = change in temperature = $1.643^oC$

Now put all the given value in the above formula, we get:

$26380J/g=0.235g\times c\times 1.643^oC$

$c=68323.38J/^oC$

Thus, the specific heat of calorimeter is $68323.38J/^oC$

Now we have to calculate the heat of combustion of caffeine.

Formula used :

$Q=c\times \Delta T$

where,

Q = heat of combustion of caffeine = ?

c = specific heat of calorimeter = $68323.38J/^oC$

$\Delta T$ = change in temperature = $1.584^oC$

Now put all the given value in the above formula, we get:

$Q=68323.38J/^oC\times 1.584^oC$

$Q=108224.23J=108.2kJ$

Now we have to calculate the moles of caffeine.

$\text{Moles of caffeine}=\frac{\text{Mass of caffeine}}{\text{Molar mass of caffeine}}$

Mass of caffeine = 0.275 g

Molar mass of caffeine = 194.19 g/mole

$\text{Moles of caffeine}=\frac{0.275g}{194.19g/mole}=0.00142mol$

Now we have to calculate the heat of combustion per mole of caffeine at constant volume.

$\text{Heat of combustion per mole of caffeine}=\frac{108.2kJ}{0.00142mol}=76197.18kJ/mole$

Therefore, the heat of combustion per mole of caffeine at constant volume is 76197.18 kJ/mole

4 0

3 years ago

What is the overall order of reaction for this rate law: Rate = k ? zero first second third

DENIUS [597]

The overall order of a reaction is directly related to the reaction mechanism of the reaction. The reaction mechanism is defined by the reaction rate equation. In this case, we are given by the equation, Rate=k. The order of this reaction is zero since the rate is not dependent on the concentration of reactants or products.

3 0

3 years ago

Read 2 more answers