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2 years ago

Help me please I really need this tomorrow

Chemistry

2 answers:

scoundrel [369]2 years ago

6 0

9.D

10.A

11.C

12.B

13.D

14.C

15.A

16.A

18.C

jok3333 [9.3K]2 years ago

3 0

9. melting point

10. balloons float because they are filled with hydrogen, a gas which is less dense than air.

11. specific gravity

12. element

13. mixture

14. sodium and chlorine

15. cutting of paper

16. condensation

17. 1 and 3

18. heat energy is released

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Describe the function of the PNS and the CNS

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The peripheral nervous system, or PNS, consists of the nerves and ganglia outside of the brain and the spinal cord. The main function of the PNS is to connect the central nervous system (CNS) to the limbs and organs.

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2 years ago

Problem PageQuestionSteam reforming of methane ( ) produces "synthesis gas," a mixture of carbon monoxide gas and hydrogen gas,

Serhud [2]

The question is incomplete. Her eis the complete question.

Steam reforming methane (CH4) produces "synthesis gas", a mixture of carbon monoxide gas and hydrogen gas, which is the starting point for many important industrial chemical syntheses. An industrial chemist studying this reaction fills a 125L tank with 20 mol of methane gas and 10 mol of water vapor at 38°C. He then raises the temperature, and when the mixture has come to equilibrium measures the amount of gas hydrogen to be 18 mol. Calculate the concentration equilibrium constant for the steam reforming of methane at the final temperature of the mixture. Round your answer to significant digits.

Answer: $K_{c}$ = 2. $10^{-2}$

Explanation: The reaction for steam reforming methane is:

$CH_{4} + H_{2}O$ ⇒ $CO_{} + 3H_{2}$

To calculate the concentration equilibrium constant, first calculate the molarity ( $\frac{mol}{L}$ ) of each molecule of the reaction.

At 38°C: At the initial temperature, there no products yet

Molarity of CH4:

CH4 = $\frac{20}{125}$ = 0.16M

Molarity of H20:

H2O = $\frac{10}{125}$ = 0.08M

At final temperature:

Molarity of H2:

H2 = $\frac{18}{125}$ = 0.144M

According to the chemical reaction, the combination of 1 mol of each reagents produces 1 mol of CO and 3 mols of H2, so, for the products, the ratio is 1:3.

Molarity of CO:

CO = $\frac{0.144}{3}$ = 0.048M

For the reagents, the proportion is 1:1, but they had an initial concentration, so, when in equilibrium, the concentration will be:

Molarity of CH4:

CH4 = 0.16 - 0.048 = 0.112M

Molarity of H2O:

H20 = 0.08 - 0.048 = 0.032M

The equilibrium constant is given by:

$K_{c} = \frac{[CO][H_{2}]^{3} }{[CH_{4}][H_{2}O ] }$

$K_{c}$ = $\frac{0.048.0.144^{3} }{0.112.0.032}$

$K_{c}$ = 2. $10^{-2}$

The concentration equilibrium constant for the process is $K_{c}$ = 2. $10^{-2}$ .

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3 years ago

Draw the Lewis structure for BCl3. How many single bonds, double bonds, triple bonds, and unshared pairs of electrons are on the

andreev551 [17]

Answer : The number of single bonds, double bonds, triple bonds, and unshared pairs of electrons on the central atom are, 3, 0, 0 and 0 respectively.

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The given molecule is, $BCl_3$

As we know that boron has '3' valence electrons and chlorine has '7' valence electrons.

Therefore, the total number of valence electrons in $BCl_3$ = 3 + 3(7) = 24

According to Lewis-dot structure, there are 6 number of bonding electrons and 18 number of non-bonding electrons.

From the Lewis-dot structure we conclude that,

The number of single bonds, double bonds, triple bonds, and unshared pairs of electrons on the central atom are, 3, 0, 0 and 0 respectively.

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3 years ago

A rock falls off a cliff and hits the ground after three seconds. What is its velocity right before it hits the ground?

Amiraneli [1.4K]

To solve this kinematics formula use the following equation:

Vf = Vi + at
Vf = 0 + (9.81 m/s^2)(3 seconds)
Vf = 29.43 m/s and or about 29.4 m/s of reported to 3 significant figures.

4 0

3 years ago

Read 2 more answers

A helium-filled balloon at 310.0 K and 1 atm, contains 0.05 g He, and has a volume of 1.21 L. It is placed in a freezer (T = 235

trapecia [35]

Answer : The value of $\Delta E$ of the gas is 2.79 Joules.