pls help me right now​

This question is asking for a method for the determination of the freezing point in a solution that does not have a noticeable transition in the cooling curve, which is basically based on a linear fit method.

The first step, would be to understand that when the transition is well-defined as the one on the attached file, we can just identify the temperature by just reading the value on the graph, at the time the slope has a pronounced change. For instance, on the attached, the transition occurs after about 43 seconds and the freezing point will be about 4 °C.

However, when we cannot identify a pronounced change in the slope, it will be necessary to use a linear fit method (such as minimum squares) to figure out the equation for each segmented line having a significantly different slope and then equal them so that we can numerically solve for the intercept.

As an example, imagine two of the segmented lines have the following equations after applying the linear fit method:

[tex]y=-3.5 x + 25\\\\y=-0.52 x + 2[/tex]

First of all, we equal them to find the x-value, in this case the time at which the freezing point takes place:

[tex]-3.5 x + 25=-0.52 x + 2\\\\-3.5 x+0.52 x =2-25\\\\x=\frac{-23}{-2.98}=7.72[/tex]

Next, we plug it in in any of the trendlines to obtain the freezing point as the y-value:

[tex]y=-3.5 (7.72) + 25\\\\y = 1.84[/tex]

This means the freezing point takes place after 7.72 second of cooling and is about 1.84 °C. Now you can replicate it for any not well-defined cooling curve.

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Spontaneous processes are processes such as;  a soluble salt dissolves when it is mixed with water, iron rusts when it exposed to salty water and a match continues to burns after it is lit.

A spontaneous process is a process that occurs without external input of energy or does not require a continuous input of energy once the process has gotten underway.

Among the options the processes which are spontaneous under standard conditions of 1 atm, 298 K and 1 M are;

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Answer:

Approximately [tex]83[/tex] minutes.

Explanation:

Look up the relative atomic mass of [tex]\rm Ag[/tex]: [tex]M({\rm Ag}) = 107.868\; \rm g \cdot mol^{-1}[/tex].[tex]\begin{aligned}Q &= e\, (n(e)) \\ &\approx 1.602 \times 10^{-19}\; \rm C \times 1.06 \times 10^{23} \\ &\approx 1.6987 \times 10^{4}\; \rm C \end{aligned}[/tex]/.

Avogadro's number: [tex]N_A \approx 6.02 \times 10^{23}\; \rm mol^{-1}[/tex].

Elementary charge: [tex]e \approx 1.602 \times 10^{-19}\; \rm C[/tex].

Calculate the quantity of [tex]\rm Ag[/tex] atoms to reduce:

[tex]\begin{aligned}& n({\rm Ag}) \\ &= \frac{m({\rm Ag})}{M({\rm Ag})} \\ &= \frac{19\; \rm g}{107.868\; \rm g \cdot mol^{-1}} \\ & \approx 0.176\; \rm mol\end{aligned}[/tex].

By the equation, it takes one electron to reduce every [tex]\rm Ag[/tex] atom. Thus, the number of electrons required to reduce [tex]0.176\; \rm mol[/tex] of [tex]\rm Ag\![/tex] atoms would be:

[tex]n(e) = n({\rm Ag}) \approx 0.176\; \rm mol[/tex].

[tex]\begin{aligned}N(e) &= n(e) \cdot N_{A}. \\ &\approx 0.176\; \rm mol \times 6.02 \times 10^{23}\; \rm mol^{-1} \\ & \approx 1.06 \times 10^{23}\end{aligned}[/tex].

Calculate the amount of charge (in coulombs) in that many electrons:

[tex]\begin{aligned}Q &= e\, (n(e)) \\ &\approx 1.602 \times 10^{-19}\; \rm C \times 1.06 \times 10^{23} \\ &\approx 16987.1 \; \rm C \end{aligned}[/tex].

A current of [tex]1\; \rm A[/tex] carries a charge of [tex]1\; \rm C[/tex] every second. Thus, the amount of time required for this current to carry that much electron would be:"

[tex]\begin{aligned}t &= \frac{Q}{I} \\ &\approx \frac{16987.1\; \rm C}{3.4\; \rm A} \\ &\approx 83.3\; \rm s \\ &\approx 5.00\times 10^{3}\; \rm s \\ &\approx 83\; \text{minutes} \end{aligned}[/tex].

Answer:

XF3 is our compound. X is unknown For the problem I am using the periodic table at this ...

Explanation:Solution for Element X is an element in period 3. Identify X given that in the molecule XH3, it exhibits hybridization sp2 . Indicate the symbol and not ...

Two or more than two atoms with different physical or chemical properties can not combine together to form an element. The element X  in period 4 with covalency 3 is Arsenic (As).

Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same. The periodic table is divided into groups and periods. depending on the number of valence electrons and the number of outermost orbit respectively.

In the given compound XH[tex]_3[/tex], the covalency of X is 3, means the valence electrons in the outermost shell of element X is 3. The only group that have valence electron 3 is group 15  that is nitrogen family. In the fourth period of group 15 we find Arsenic element.

Therefore the element X  in period 4 with covalency 3 is Arsenic (As).

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Answer:

This tells you that one mole of sulfur atoms, S , has a mass of 32 g

Answer:

------------------------------

Explanation:

---------------

The heat produced by 4.5 moles of magnesium when burnt is 2700 kJ.

A thermochemical reaction is a reaction in which the amount of heat lost or gained is included in the reaction equation. The thermochemical reaction equation for the combustion of magnesium is shown as follows;

2 Mg(s) + O2(g) → 2 MgO(s) + 1200 kJ

From the reaction equation;

2 moles of magnesium produced 1200 kJ of heat

4.5 moles of magnesium will produce 4.5 moles × 1200 kJ/2 moles

= 2700 kJ

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Answer:

Natural source of light

Explanation:

Answer:

i dont speak mexican

Explanation:

The molarity of the acid, HCl solution is 0.103 M

We'll begin by calculating the number of mole in 0.2329 g of Na₂CO₃

Mass of Na₂CO₃ = 0.2329 g

Molar mass of Na₂CO₃ = (23×2) + 12 + (16×3) = 106 g/mol

Mole = mass / molar mass

Mole of Na₂CO₃ = 0.2329 / 106

Na₂CO₃ + 2HCl —> 2NaCl + H₂O + CO₂

From the balanced equation above,

1 mole of Na₂CO₃ reacted with 2 moles of HCl.

Therefore,

0.0022 mole of Na₂CO₃ will react with = 0.0022 × 2 = 0.0044 mole of HCl

Mole of HCl = 0.0044 mole

Volume = 42.87 mL = 42.87 / 1000 = 0.04287 L

Molarity = mole / Volume

Molarity of HCl = 0.0044 / 0.04287

Thus, the molarity of the acid, HCl solution is 0.103 M

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Answer:

Yes it is B,D.

Explanation:

Each box represents an element and contains its atomic number, symbol, average atomic mass, and (sometimes) name. The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups.

Answer:

6am

Explanation:

answer this please thank you

Answer:

Cr

Explanation:

Cr goes from +3 to +6 and when it increases it means is being oxidized.

The element being oxidized in the redox reaction is Cr. Oxidation state helps to determine the amount of oxidation which an atom undergoes. An increase in oxidation state or number signifies oxidation has taken place.

A decrease in oxidation state depicts reduction has taken place. In this

scenario, the element Cr has a change in oxidation state from +3 to +6 which

signifies oxidation took place in the atoms of the element. This is why Cr will

be the right option.

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Answer: Hi! The partial pressure of CH4 is

=1 atm

Explanation:

The partial pressure of methane in the mixture of methane and ethane has been 1 atm.

Partial pressure has been the pressure exerted by a gas in the solution or mixture. The partial pressure of each gas has been the total pressure of the gaseous mixture.

The partial pressure of the gas has been dependent on the volume, temperature, and concentration of the gas.

The given methane has a partial pressure of 1 atm in the 15 L vessel. The addition of ethane results in the change in the total pressure of the mixture, as there have been additional moles of solute that contributes to the solution pressure.

However, since there has been no change in the concentration and volume of methane, the pressure exerted by methane has been the same. Thus, the partial pressure of methane has been 1 atm.

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Answer:

[tex]11 \times 6.022 \times {10}^{23} \\ = 66.242\times {10}^{23} \: of \: \\ water \: molecules[/tex]

% Composition of elements:

Atomic mass of given elements:

Now, divide % composition by Atomic mass:

[tex]\footnotesize\implies Mg = \dfrac{\% \: Composition}{Atomic \: mass} = \dfrac{75}{24} = \bf 3.125[/tex]

[tex]\footnotesize\implies O = \dfrac{\% \: Composition}{Atomic \: mass} = \dfrac{25}{16} = \bf 1.5625[/tex]

Simplest Ratio:

[tex]\footnotesize\implies Mg = \dfrac{3.125}{1.5625} = 2[/tex]

[tex]\footnotesize\implies O = \dfrac{1.5625}{1.5625} = 1[/tex]

Empirical Formula:

[tex]\footnotesize\implies \underline{ \boxed{ \red{ \bf Empirical \: Formula = Mg_2O}}}[/tex]

The empirical formula will be [tex]Mg_{2}[/tex] .

The simplest entire number fraction of atoms contained in a chemical molecule is its empirical formula.

Calculation of empirical formula:

It is given that, composition of Mg = 75 %, composition of oxygen  = 25%.

It is known that, atomic mass of Mg = 24 g, atomic mass of oxygen = 16g.

By dividing % composition by atomic mass of given elements:

Mg = % composition / %atomic mass

= 75 / 24

= 3.125

Oxygen (O) = % Composition / atomic mass

= 25 / 1.56

Now, calculate simplest ratio of Mg and O.

For Mg = 3.125 / 1.56

= 2.

For O = 1.56 / 1.56

= 1

So, the empirical formula will be [tex]Mg_{2}O[/tex].

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Answer:

B

Explanation:

Option B is the correct answer. When you add 7 in front of the O2 in the left side, and then you add 4 and 6 in front of NO2 and H2O respectively, the number of oxygen atoms is the same in both sides.

The number of moles of mercury can you get you collect and process the entire volume of 1250 m3 of the water in the pond is 8.7  × 10^-5 moles.

First, we must convert the concentration of mercury in the pond to molar concentration using the relation;

Mass concentration = Molar concentration × molar mass

Molar concentration = Mass concentration /molar mass

Molar mass of mercury = 201 g/mol

Molar concentration = 14 × 10^-9 g/201 g/mol = 6.97 × 10^-11 M

Volume of solution = 1250 m3 or 1250000 L

Number of moles = concentration × volume

Number of moles =  6.97 × 10^-11 M ×  1250000 L

Number of moles = 8.7  × 10^-5 moles

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Answer:

1.1 million pounds

Explanation:

Answer:

1.1 million pounds

Explanation:

that's a lot of water above us!!

Answer:The plates are not fixed but are constantly moving atop a layer of solid and molten rock called the mantle. The Ring of Fire is a string of volcanoes and sites of seismic activity, or earthquakes, around the edges of the Pacific Ocean. ... A hotspot is a place in the middle of a tectonic plate where hot magma rises.

Explanation:

Answer:  a.1.37  b.4.11 c.6.00  d.12.3

Explanation:

Answer:

answer is 4.6×10 with exponent 7

Answer:

[tex]4.6\times10^{-7}[/tex]

Explanation:

Remember that if the decimal point is to the right then the exponent is a negative.

[tex]4.6\times10^{-7}[/tex]

Move the decimal point to the left:

[tex].0.0.0.0.0.0.4.6[/tex]

[tex].0.0.0.0.0.0.4.6=0.00000046[/tex]

Hope this helps

Answer:

Na2S

Explanation:

hope this helps

Answer:

None of them

Explanation:

The number of moles in 75ml is 0.01875moles while in 25ml is 0.004375 and in 129 ml is 0.018705.

REMEMBER: Molarity is the number of moles per litre so in order to get the number of moles you multiply the molarity of the substance by the quantity of the substance in litres.

129 mL of 0.145 M solution of KCl solution has the same number of moles of KCl as 75.00 mL of 0.250 M solution of KCl. Therefore, option B is correct.

Molarity is defined as the number of moles of a solute in one liter of solution. A solution's molarity is also known as its molar concentration.

To calculate the molarity of a solution, divide the number of moles of solute by the total volume of solution in liters.

Molarity is a concentration unit that is defined as the number of moles of dissolved solute per liter of solution. Molarity is expressed as the number of millimoles per milliliter of solution when the number of moles and volume are divided by 1000.

Given:

number of mol = M ×V

= 0.250 M × 0.0750 L

= 1.87 × 10^-2 mol

volume, V = 1.29*10^2 mL

= 0.129 L

use:

number of mol,

n = Molarity × Volume

= 0.145 × 0.129

= 1.87 × 10^-2 mol

Thus, option B is correct.

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Answer:

New volume = 6.0L

Explanation:

Make a list of variables given in the question, and what we want to find:

Initial volume (L) = Vi = 3.1

Initial temperature (K) = Ti = 193

New temperature (K) = Tn = 374

New volume (L) = Vn

We have volumes and temperatures given and we're talking about gas, the equation including both these variables that should come to mind is the ideal gas equation:

PV = nRT

P = pressure (Pa)

n = number of moles

R = gas constant = 8.31

Now, we construct an equation we can solve to get the new volume:

P(Vn) = nR(Tn)

And insert the values we know:

P(Vn) = n(8.31)(374)

P(Vn) = n·3107.94

The equation contains 3 unknown variables;

We should first try to see if we can eliminate the 2 we are not interested in, namely P and n;

What we should recognise is that the pressure and number of moles will not change upon warming the balloon;

Firstly, heating the gas inside the balloon doesn't add anything to the balloon, i.e. doesn't increase the moles of gas, it simply raises the energy of the gas particles already within the balloon, so n will not change;

Secondly, I think there is a mistake in the question, it should read "assume constant pressure" in the brackets, since the temperature does change, which we are told;

Also, we can assume normal atmospheric pressure inside and outside the balloon as would be the case ordinarily;

What we want to do with this information is rearrange the equation we constructed to have these 2 constant or unchanging variables on one side and everything else on the other, so:

[tex]\frac{P}{n} = \frac{3107.94}{V_{n} }[/tex]

Next, we construct an equation for the balloon before warming:

P(Vi) = nR(Ti)

P(3.1) = n(8.31)(193)

P·3.1 = n·1603.83

Once again, rearrange to get P and n on one side of the equation and everything else on the other:

[tex]\frac{P}{n} = \frac{1603.83}{3.1} \\\\ \frac{P}{n} = 517.364516[/tex]

Now, we have two equations for P/n, we can eliminate P/n since both these values remain the same before and after warming the balloon as previously established:

[tex]\frac{3107.94}{V_{n} } = \frac{P}{n} = 517.364516 \\\\ \frac{3107.94}{V_{n} } = 517.364516 \\\\[/tex]

Now, rearrange and solve for Vn:

[tex]\frac{3107.94}{V_{n} } = 517.364516 \\\\ V_{n} = \frac{3107.94}{517.364516} \\\\ V_{n} = 6.00725...[/tex]

Vn = 6.0L