HELPP PLEASE
this is a weird place to ask but does anyone know a good physical science experimental project that the scientific method can be used on? with homemade materials that doesn’t take more than 2 days to do?

Answer:

PCI3

Explanation:

It does not obey the octet rule on the nitrogen atom.

Answer:

you see le bear

you brain sends signals

your heart and lungs receive said signals

spring to action

Answer:

A. Decrease in temperature

Explanation:

The statement indicates an endothermic chemical reaction is "Decrease in temperature".

Endothermic reactions generate products by absorbing heat energy from the environment.

The temperature of the reaction mixture rises as energy is released in an exothermic process. The temperature drops when energy is absorbed in an endothermic reaction. A thermometer can be used to monitor temperature changes in the reaction mixture.

An endothermic reaction happens when the temperature of an isolated system drops while the temperature of its surroundings rises. The overall heat of reaction in endothermic reactions is positive (q > 0).

Hence the correct option is A.

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Answer: 0.79 atm

Explanation:

The Ideal Gas Law is PV=nRT.

since both Ar and O2 have the same volume and temperature, the only variable causing the differnce in pressure betwwen the 2 gases is the number of moles

the total pressure = the partial pressure of Ar + the partial  pressure of O2

1.024 atm = 0.447 amt + ?

so  

the total pressure of the bottle is 1.024 atm, what is the partial

pressure of O2 in the bottle? is PV

Answer:

It is a covalent bond because both carbon and oxygen are nonmetals. The formula will be CO² because the electrons between the atoms are being shared equally.

Answer:

Option C

Explanation:

CO₂ is a covalent bond because we know that both elements are nonmetals. The carbon atoms shares 2 electrons with each oxygen atom and each oxygen atom shares two electrons with the carbon atom. CO₂ forms a nonpolar covalent bond, meaning that the electrons are shared equally.

Answer:

C

Explanation:

because an ice is a solid and when it melts it becomes a liquid

Answer:

C

Explanation:

1) Which example shows a change in a state

of matter?

A. Liquid pouring

2

B. Wood Burning

1

C. Ice Melting

C  when ice melts it goes from a solid to a liquid state

Considering the reaction stoichiometry, the enthalpy change if enough propane was burned to give off 12 moles of carbon dioxide gas is 8228 kJ.

The balanced reaction is:

C₃H₈(g) + 5 O₂(g) → 3 CO₂(g) + 4 H₂O(l)

The heat of combustion of propane, C₃H₈, is -2057 kJ/mol. This is, 2057 kJ is released for every 1 mol C₃H₈.

So to determine the enthalpy change if enough propane was burned to emit 12 moles of carbon dioxide, you must take into account the stoichiometry of the reaction.

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Then you can apply the following rule of three: if by stoichiometry 3 moles of CO₂ are produced by 1 mole of C₃H₈, 12 moles of CO₂ are produced by how many moles of C₃H₈?

[tex]amount of moles of C_{3} H_{8} =\frac{12 moles of CO_{2}x1 mole of C_{3} H_{8} }{3 moles of CO_{2}}[/tex]

amount of moles of C₃H₈= 4 moles

So to determine the enthalpy change, you can apply the following rule of three: If for each mole of C₃H₈ 2057 kJ are released, for 4 moles of C₃H₈ how much heat is released?

[tex]Heat released=\frac{4 molesx2057 kJ}{1 mole}[/tex]

Heat released= 8228 kJ

The enthalpy change if enough propane was burned to give off 12 moles of carbon dioxide gas is 8228 kJ.

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A user dissolves exactly 1 g of ketamine in 1/4 cup of water.

Given 1 cup = 236.5 mL, the volume of 1/4 cup of water is:

1/4 cup × (236.5 mL/1 cup) = 59.13 mL

1 g of ketamine is dissolved in 59.13 mL of water. The concentration of ketamine, in mg/mL, is:

C = 1000 mg / 59.13 mL = 16.91 mg/mL

The volume of this solution that a 59.0 kg user (body mass) would have to consume to experience a high at 0.600 mg/Kg is:

[tex]59.0 kgBM \times \frac{0.600mgKetamine}{1kgBM} \times \frac{1mL Soluiton}{16.91mgKetamine} = 2.09 mL[/tex]

The volume of this solution that a 59.0 kg user (body mass) would have to consume to become unconscious at 2.00 mg/kg is:

[tex]59.0 kgBM \times \frac{2.00mgKetamine}{1kgBM} \times \frac{1mL Soluiton}{16.91mgKetamine} = 6.98 mL[/tex]

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The enthalpy ΔH of combustion is - 804 kJ. The change in internal energy ΔE of the reaction process is -801 kJ

The objective of this question is to determine the value of ΔH and ΔE of combustion is for 1 mole of methane.

If we look closely at the question, we will realize that at constant pressure, methane burns and produces heat of 804 kJ into the surroundings.

Since heat is released;

ΔH = -804 kJ

It also does a work of 3kJ, since work is done on the system

W = - 3kJ

According to the first law of thermodynamics;

ΔE = ΔH  -  W

ΔE = (-804 - (-3 )) kJ

ΔE = -801 kJ

Therefore, we can conclude that the in 1 mole of methane, the enthalpy ΔH of combustion is - 804 kJ. The change in internal energy ΔE of the reaction process is -801 kJ

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Answer:

6,25 gm

Explanation:

4. The half-life of C-14 is 30 years. If a scientist had 100.0 g at the beginning, how

many grams would be left after 120 years has elapsed?

10 years would be 120/30 = 4 half lives0

s0 the fraction of c-14 left would be four (1/2) multiplied together

1/2 X 1/2 X 1/2 X 1/2 = 1/16

SO 1/16 OF THE 100.0 gm would be left

100.0/16  = 6,25 gm

Answer:

for better understanding and visual understanding

Answer:

We can say that we need 171 g barium hydroxide needed to make one model equals solution.

Explanation:

I hope this answered your question.

171 gram of  Ba(OH)2, in grams, is needed to make a 1.00 m aqueous solution.

Mass is the quantity of matter. The mass is calculated by the density divide by the volume.

In 1.00 solution, the mass of Ba(OH)2 is 171 gram.

Thus, the mass of Ba(OH)2 is 171 gram.

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Answer:

B) Sterile droppers and petri dishes

The best way to balancing a combustion equation of an organic compound, like the one in the question, is to start balancing the carbon, then the hydrogen and finish with the oxygen. For that you have to split the hydrocarbon into individual elements. And once you have finished you shall always try to reduce the coefficient if possible. Therefore, the answers are A. and C.

Answer:

Calculate the freezing point of a solution of 3.46 g of a compound,X,in 160 g of benzene. When separate sample of X was vaporised, its density was found 3.27 g/L at 116 c and 773 torr. The freezing point of pure benzen is 5.45 c, and kf is 5 .12 c/m.

Explanation:

First determine molar mass from

P*molar mass = density*R*T

Solve for molar mass. Then

moles = grams/molar mass

Solve for moles

molality = moles/kg solvent

Solve for molality

delta T = Kf*m

Solve for delta T, then convert to freezing point

Answer:

38.3 g

Explanation:

8) What mass of chlorine reacts with 20.0 g of iron to form iron(III) chloride?​

first write, then balance the equation

Fe + Cl2-------------> FeCl3

2Fe + 3Cl2----------> 2FeCl3

2 moles of Fe require 3 moles of Cl2

the atomic mass of Fe is 56

20/56= 0.36 moles of Fe

this requires o.36 X 3/2 = 0.54 moles of Cl2

Cl2 has a molar mass of 35.5 X 2=71

1 mole of Cl2 is 71g

0.54 moles is 0.54 X 71 g= 38.3 g

The mass of chlorine reacts with 20.0 g of iron to form iron(III) chloride is 38.3 g.

Mass is defined as a numerical representation of the fundamental characteristic of all matter, inertia.

It can also be defined as a dimensionless number used to describe the mass of a particle or item.

[tex]\rm 2Fe + 3Cl_2\rightarrow2FeCl_3[/tex]

As per the reaction 3 mole of chlorine is required for 2 mole of fluorine.

Atomic mass of fluorine = 56

Moles of Fe = 20 / 56

                    =  0.36 moles

This require 0.36 x 3/2 = 0.54 moles of Cl₂

Molar mass of Cl = 35.5

So for Cl₂ = 2 x 35.5 = 71 moles

For 1 mole of Cl₂ = 71 moles is needed

So, for 0.54 moles = 71 x 0.54

                               = 38.3 g

Thus, the mass of chlorine reacts with 20.0 g of iron to form iron(III) chloride is 38.3 g.

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