What are the two sources of energy for the Earth system?

Answer:

it talks about reality ..how animals and human came to existence and how they disappear ..this is evolution

the environment chooses those who best fit in it and others are selected ..as in die ..this is referred to as natural selection

and further in this theory .animals produce off springs who survive in the environment

Answer:

Option C. 11

Explanation:

We'll begin by calculating the concentration of the hydroxide ion [OH¯] in the solution. This can be obtained as follow:

In solution, KOH will dissociate as follow:

KOH (aq) <=> K⁺(aq) + OH¯(aq)

From the balanced equation above,

1 mole of KOH reacted to produce 1 mole of OH¯.

Therefore, 1×10¯³ M KOH will also react to produce 1×10¯³ M OH¯.

Thus, the concentration of hydroxide ion [OH¯] in the solution is 1×10¯³ M

Next, we shall determine the pOH of the solution. This can be obtained as follow:

Concentration of hydroxide ion [OH¯] = 1×10¯³ M

pOH =?

pOH = –Log [OH¯]

pOH = –Log 1×10¯³

pOH = 3

Finally, we shall determine the pH of the solution. This can be obtained as follow:

pOH = 3

pH =?

pH + pOH = 14

pH + 3 = 14

Collect like terms

pH = 14 – 3

pH = 11

Answer:

0.68°C and 0°C.

Explanation:

The average freezing point of sucrose is 0.68°C whereas the average freezing point is 0°C. Both at these temperatures, turn from liquid into solid state. This point is also called transition point because at this point transition of state occurs of both compounds. When the temperature increases, this solid state is again turn into liquid form so temperature is responsible for this change of states of sucrose and water.

Respuesta:

4.26 M; 12.8 N

Explicación:

Primer paso: Calcular la concentración volumétrica (Cv)

Usaremos la siguiente expression.

Cv = Cg × ρ

Cv = 30 g%g × 1.39 g/mL = 41.7 g%mL

Segundo paso: Calcular la molaridad

La concentración volumetrica es 41.7 g%mL, es decir, hay 41.7 gramos de soluto cada 100 mL de solución. Usaremos la siguiente fórmula para molaridad.

M = masa de soluto / masa molar de soluto × litros de solución

M = 41.7 g / 97.99 g/mol × 0.1 L = 4.26 M

Tercer paso: Calcular la normalidad

Usaremos la siguiente fórmula.

N = M × Z

donde Z para un ácido es igual al número de protones.

N = M × Z

N = 4.26 mol/L × 3 eq/mol = 12.8 N

Explanation:

Given the amount of fluorine is ---- 1.25 mol.

What is the mass of given fluorine in grams?

Since

[tex]Number of moles =\frac{given mass of the substance}{its molecular mass}[/tex]

To get the mass of the substance in grams, multiply the given number of moles with the molecular mass of the substance.

Hence, among the given options, the correct answer is the last option that is

Multiply the atomic mass of fluorine by 1.25.

Answer:

Multiply the atomic mass of fluorine by 1.25.

Explanation:

i got it right on the exam!! :)

Answer:

0.06 liter

Explanation:

First, let us look at the equation of the first reaction:

2HCl + Mg ----> MgCl2 + H2

2 moles of HCl requires 1 mole of Mg for complete reaction.

Mole of HCl available = molarity x volume

                                    0.2 x 50/1000 = 0.1 mole

Mole of Mg available = mass/molar mass

                                    0.6/24.3 = 0.02 mole.

Thus, HCl is in excess by 0.1 mole.

Now, let us look at the second reaction:

HCl + NaOH ----> NaCl + H2O

mole ratio of HCl to NaOH is 1:1

Remember that 0.1 mole HCl is left from the first reaction. Thus, 0.1 mole of the alkaline would also be needed.

Hence, volume of NaOH needed = mole/molarity

                        0.1/1.67 = 0.06 dm3

The volume of alkaline needed would, therefore, be 0.06 liter.

Explanation:

The boiling point of a substance is 293°C.

The boiling point is the temperature at which the vapor pressure of a liquid becomes equal to the atmospheric pressure.

So, at the boiling point:

The vapor pressure =atmospheric pressure = 1 atm.

To get the vapor pressure of the substance at 220°C is definitely less than 1 atm.

Since, as the temperature increases, the vapor pressure of the liquid increases.

Answer:

D. To ensure the cooling process is not affected by surrounding temperature

Explanation:

The conical flask acts as a temperature jacket.

The conical flask is used in freezing point of the naphthalene activity because to ensure the cooling process is not affected by surrounding temperature.

In the freezing point determination of naphthalene, a conical flask is used to hold the naphthalene sample and a thermometer. The conical shape of the flask allows for efficient stirring of the naphthalene as it is heated and cooled, ensuring that the temperature is evenly distributed throughout the sample.

The conical flask is also used to protect the naphthalene sample from any external temperature fluctuations that could affect the cooling process. By placing the flask in an ice bath, the cooling process can be closely monitored and controlled, allowing for accurate determination of the freezing point.

Therefore, the primary reason why a conical flask is used in the freezing point determination of naphthalene is to ensure that the cooling process is not affected by surrounding temperature.

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Answer:

tissues is the answer to your question

Answer:

I don't know yr language

nobody can say it is uncertain but in my opinion it will grow quickly in the next 10 years

Answer:

False

Explanation:

sea floor spreading is not consistent at all mid ocean ridges.

Explanation:

number of moles=mass/molecular mass

molecular mass of calcium hydroxide=74

n=m/mr

=48.6/74

=0.65g/mol

I hope it helps

The number of moles of calcium hydroxide in a 48.6 g is 0.65 mol

The mole, symbol mol, is the SI base unit of amount of substance.

The quantity amount of substance is a measure of how many elementary entities of a given substance are in an object or sample.

Formula used :

Number of moles = mass / molecular mass

Molecular mass of calcium hydroxide = 74

n = m / mm

= 48.6 / 74

= 0.65 mol

Therefore, The number of moles of calcium hydroxide in a 48.6 g is 0.65 mol

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Answer:

Explain the advantages of subdividing science into many different areas. Advantages-It allows scientists to delve into a specific topic easier, so that they can go deeper.

hope it helps

Answer:

Science is a vast subject. Scientists have classified it into different areas/branches so that they do not get their concepts mixed or overlapped. We can think of all the sub-branches as different topics studied under one main subject, science. We just divide the main subject so that we can study each of the topic clearly and individually. Science is such a vast subject that most of its sub branches are not even related to each other or interlinked, like computer science and biology. If we did not have subdivisions in science, can you imagine a person studying biology, computer science, chemistry, physics, phycology etc all at the same time, simultaneously? Of course not! That's why, in order to get a clear understanding of each topic, we divide science into different areas.

Hope that helps...

Answer:

transition state is a point in which electrons been removed from the atom

Answer:

The highest energy structure in the reaction coordinate.

Explanation:

Answer:

I think it is C

Explanation:

Hope this helps!! :)

If I'm wrong, then greatest apologies

Answer:

Al2O3 + 6HCl ==> 2AlCl3 + 3H2O ... balanced equation

moles Al2O3 present = 30.0 g x 1 mol/101.96 g = 0.294 moles

moles HCl present = 30 g HCl x 1 mol/36.5 g = 0.822 moles HCl

HCl is LIMITING as it takes 6 moles HCl for each 1 mol Al2O3 and here that is not enough. It will run out first.

Now, using the limiting reactant, we find the moles and mass of AlCl3 that can be formed.

0.822 moles HCl x 2 moles AlCl3/6 moles HCl = 0.274 moles AlCl3 formed

mass of AlCl3 = 0.274 moles AlCl3 x 133 g/mole = 36.4 g AlCl3 formed

Answer:

a. H2O: dihydrogen monoxide

b. PCl5: Phosphorus pentachloride

c. SiF4: Silicon tetrafluoride

d. N20: dinitrogen oxide

Answer:

two atoms

Explanation:

Answer:

the reaction between vinegar and baking soda, the reactants are vinegar (acetic acid) and baking soda (sodium bicarbonate). The products are sodium acetate, water, and carbon dioxide gas.

Answer:

The electrode that removes ions from solution

Explanation:

Each electrochemical cell consists of an anode and a cathode. Oxidation occurs at the anode and reduction occurs at the cathode.

At the anode, ions move from the electrode into the solution while at the cathode ions move from the solution to the electrode.

At the cathode, metal ions accept electron(s) and become deposited on the electrode hence this electrode removes ions from solution. This is reduction.

Answer:

[tex]\boxed {\boxed {\sf 232.9 \textdegree C}}[/tex]

Explanation:

This question asks us to find the temperature change given a volume change. We will use Charles's Law, which states the volume of a gas is directly proportional to the temperature. The formula is:

[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]

The volume of the gas starts at 250 milliliters and the temperature is 137 °C.

[tex]\frac{250 \ mL}{137 \textdegree C}= \frac{V_2}{T_2}[/tex]

The volume of the gas is increased to 425 milliliters, but the temperature is unknown.

[tex]\frac{250 \ mL}{137 \textdegree C}= \frac{425 \ mL}{T_2}[/tex]

We are solving for the new temperature, so we must isolate the variable T₂. First, cross multiply. Multiply the first numerator and second denominator, then multiply the first denominator and second numerator.

[tex]250 \ mL * T_2 = 137 \textdegree C * 425 \ mL[/tex]

Now the variable is being multiplied by 250 milliliters. The inverse of multiplication is division. Divide both sides of the equation by 250 mL.

[tex]\frac{250 \ mL * T_2}{250 \ mL}=\frac{ 137 \textdegree C * 425 \ mL}{250 \ mL}[/tex]

[tex]T_2=\frac{ 137 \textdegree C * 425 \ mL}{250 \ mL}[/tex]

The units of milliliters (mL) cancel.

[tex]T_2=\frac{ 137 \textdegree C * 425 }{250 }[/tex]

[tex]T_2= \frac{58225}{250} \textdegree C[/tex]

[tex]T_2=232.9 \textdegree C[/tex]

The temperature changes to 232.9 degrees Celsius.

Answer:

d. The electron-pair geometry is tetrahedral, the molecular geometry is tetrahedral.

Explanation:

According to Valence Shell Electron Pair Repulsion Theory, the shape of a molecule depends on the number of electrons pairs surrounding the valence shell of the central atom in the molecule.

In CH3Cl, the central atom is carbon. Carbon has four regions of electron density surrounding it and no lone pairs. Lone pairs cause molecules to deviate from the expected geometry.

Since CH3Cl has no lone pairs on the carbon central atom, both the molecular and electron pair geometries are tetrahedral.

In CH₃Cl, the electron-pair geometry is trigonal-planar, and the molecular geometry is bent. Therefore, option C is correct.

According to VSEPR (Valence Shell Electron Pair Repulsion) theory, the electron pairs around the central atom in CH₃Cl will arrange themselves to minimize repulsion, resulting in a specific geometry.

In CH₃Cl, the central atom is carbon (C), and it is surrounded by three hydrogen atoms (H) and one chlorine atom (Cl).

The electron-pair geometry is determined by the arrangement of these electron pairs.

Molecular geometry considers only the atoms around the central atom, not the lone pairs.

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Answer:

C

Explanation:

∂S represents change in entropy.

Answer:

Answer to the following question is as follows;

Explanation:

Alkynes' vapour pressure and normal boiling points are altered when chain length grows, since vapour pressure rises while boiling point falls.

Vapour pressure always include pressure entered by vapour with its condensed phase, pressure include molecules force of attraction include vapour

Answer:

TIMED HELP ASAP

19.11 g of MgSO₄ is placed into 100.0 mL of water. The water's temperature increases by 6.70°C. Calculate ∆H, in kJ/mol, for the dissolution of MgSO₄. (The specific heat of water is 4.184 J/g･°C and the density of the water is 1.00 g/mL). You can assume that the specific heat of the solution is the same as that of water.

Answer:

-21.03 kJ/mol

Explanation:

∆H is enthalpy. Enthalpy is the total heat content of a system.

So we can establish that ∆H = q (heat)

The formula for heat (q)

q = cm∆T

c = specific heat capacity

m = mass of substance

∆T= change of temperature

Since we are calculating the enthalpy of the SOLUTION. We must account for both the mass of water and the mass of MgSO₄ in our q formula.

All you gotta do is plug and chug at this stage.

∆H = q     = cm∆T = (4.184)(19.11+100.0)(6.70) = 3338.986808 Joules

We have now calculated the heat (aka enthalpy) of the solution.

BUT

Remember! The problem asked for enthalpy in kj....

Use this conversion factor.

1000 J = 1 kJ

3338.986808 Joules * 1kJ/1000 J = 3.338986808 kJ

We were asked to find ∆H for the dissolution of MgSO4  in units of kj/mol so we are not finished.

Take the grams of MgSO4 in the problem  and convert it into moles using its molar mass.

MgSO4 molar mass = 120.3676 g

1 mol = 120.3676 g MgSO4   <---- Use this as a conversion factor

19.11 g MgSO4 * 1 mol MgSO4/120.3676 g = 0.15876365 mol MgSO4

Now that you've calculated the moles of MgSO4 in this solution. You can divide your heat by it.

q dissolution = 3.338.986808 kJ/ 0.15876365 mol =  21.03 kj/mol

Note that the problem tells us that the temperature of water increases.

This means that the water is experiencing an endothermic process (heat is being absorbed from MgSO4) . Mathematically, this would be indicated by a positive sign. ---> +q

We can assume MgSO4 is losing heat as it is placed into the water. It is experiencing an exothermic process (heat is being lost).  Mathematically, this would be indicated by a negative sign. ----> -q

So if we're calculating the enthalpy for the dissolution of MgSO₄ ....the value we've arrived at must be negative.

Answer

∆H = 21.03 kj/mol :)))))

I hope that helped...I feel like my explanation was a bit convoluted.