A fossil is 3 half-life old. Measured Uranium-235 has half-life of 704 million years. How many years old is this fossil?

The specific heat of an unknown substance is 0.96 J/(g·ºC).

The specific heat capacity of a substance can be described as the quantity of heat needed to raise the temperature in one unit of substance by 1 degree Celcius.

Whenever the heat is lost or absorbed there is a change in the temperature of the substance:

Q = mCΔT

Given, the amount of energy released, Q = 12 cal

The initial temperature of the substance = 25.0ºC

The final temperature of the substance = 20.0ºC

The change in the temperature of a substance, ΔT = 25 -20 = 5°C

The mass of the substance, m = 2.50 g

We have to find the specific heat capacity of an unknown substance.

12 cal = 2.50 g × C × 5°C

C = 0.96 J/(g·ºC)

Therefore, the specific heat capacity of an unknown substance is equal to 0.96 J/(g·ºC).

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The amount of heat needed to raise a substance's temperature by one degree Celsius per gram is known as specific heat. The specific heat in J/(gºC) of an unknown substance is 0.96 J/gºC.

The amount of heat needed to increase the temperature of the entire substance by one degree is the heat capacity of a substance. Specific heat capacity is what is used when the substance's mass is equal to one.

The hydrogen bonds in water, which account for its high specific heat.

The expression used to calculate the specific heat capacity is:

Q = mcΔT

Here Q = 12 Cal

m = 2.50 g

T₁ = 25.0ºC

T₂ = 20.0ºC

ΔT = 5°C

12 cal = 2.50 g × c × 5°C

c = 0.96 J/gºC

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The mass of fluorine that were formed is 592 mg

From the question, we are to determine the mass of fluorine formed

First, we will write the balanced chemical equation for the decomposition reaction

The balanced chemical equation for the reaction is

CaF₂ → Ca + F₂

This means

1 mole of calcium fluoride decomposes to give 1 mole of calcium and 1 mole of fluorine

Now, we will determine the number of moles of calcium produced

From the given information,

Mass of calcium produced = 625 mg = 0.625 g

Using the formula,

[tex]Number\ of \ moles =\frac{Mass}{Atomic\ mass}[/tex]

Atomic mass of calcium = 40.078 g/mol

Then,

Number of moles of calcium produced = [tex]\frac{0.625}{40.078}[/tex]

Number of moles of calcium produced = 0.01559 mole

Since

1 mole of calcium fluoride decomposes to give 1 mole of calcium and 1 mole of fluorine

Then,

0.01559 mole of calcium fluoride will decompose to give 0.01559 mole of calcium and 0.01559 mole of fluorine

∴ Number of mole of fluorine formed was 0.01559 mole

Now, for the mass of fluorine formed

Using the formula,

Mass = Number of moles × Molar mass

Molar mass of fluorine = 38 g/mol

Then,

Mass of fluorine formed = 0.01559 × 38

Mass of fluorine formed = 0.59242 g

Mass of fluorine formed = 592.42 mg

Mass of fluorine formed ≅ 592 mg

Hence, the mass of fluorine that were formed is 592 mg.

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Based on the vapor pressure of the pure substances, the mole fraction of pentane is 0.45 and mole fraction of hexane at equilibrium is 0.60.

Vapor pressure of of a liquid is the pressure that is excreted on the walls of a sealed vessel by the molecules of the liquid that have been converted to gaseous phase.

TO determine the mole fraction of pentane in the solution, we use the vapor pressure of the pure substances.

Let the mole fraction of pentane in the mixture be X.

The mole fraction of hexane will be 1 - X

Vapor pressure of solution = 383 torr

(mole fraction of pentane × vapor pressure of pentane) + (mole fraction of hexane × vapor pressure of hexane) = 383 torr

X × 511 + (1 - X) × 150 = 383

511X - 150X + 150 = 383

511X = 233

X = 0.45

Also , at equilibrium, the vapor pressure of pentane = 0.45 × 511 = 230 torr

mole fraction of hexane in the vapor that is in equilibrium with this solution = 230/383

mole fraction of hexane at equilibrium = 0.60

Therefore, the mole fraction of pentane is 0.45 and mole fraction of hexane at equilibrium is 0.60.

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The equation that shows how frequency is related to velocity and wavelength is f = v / λ (Option A)

This is defined as the number of oscillations made in one second. It is expressed as

Frequency (f) = 1 / period (T)

f = 1 / T

The velocity, frequency and wavelength of a wave are related according to the following equation

v = λf

Making f the subject, we have

f = v / λ

Thus, we can conclude that the correct answer to the question is:

f = v / λ (Option A)

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Answer:

22.25 °C

Explanation:

Determine the final temperature when a 25.0 g piece of iron at 85.0 °C is placed into 75.0 grams of water at 20.0 °C.

Answer:

About 11.0 moles.

Explanation:

We are given a bottle filled with 1.00 L of sulfur hexafluoride (SF₆) and we want to determine the number of moles of the liquid that is present.

First, determine its mass with the given density:

[tex]\displaystyle \begin{aligned}\rho & = \frac{m}{V} \\ \\ m & = \rho V \\ \\ & = \left(\frac{1.60\text{ g}}{\text{mL}}\right)(1.00\text{ L})\left(\frac{1000\text{ mL}}{1\text{ L}}\right) \\ \\ & = 1.60\times 10^3 \text{ g}\end{aligned}[/tex]

The molecular weight of SF₆ is 146.07 g/mol. Hence:

[tex]\displaystyle 1.60\times 10^3\text{ g SF$_6$} \cdot \frac{1\text{ mol SF$_6$}}{146.07\text{ g SF$_6$}} = 11.0\text{ mol SF$_6$}[/tex]

Therefore, about 11.0 moles of sulfur hexafluoride is present.

Answer:

a

Explanation:

On drawing the structure, the most Carbon atoms in a row is 5

The remaining two carbon atoms are connected to the 2nd carbon atom

IUPAC name is :

Taking into account the Brønsted-Lowry acid-base theory, the reaction between hypoiodous acid and water is:

HOI + H₂O ⇄ OI⁻ + H₃O⁺

The Brønsted-Lowry acid-base theory (or the Brønsted-Lowry theory) identifies acids and bases based on whether the species accepts or donates protons or H⁺.

According to this theory, acids are proton donors while bases are proton acceptors. That is, an acid is a species that donates an H⁺ proton while a base is a chemical species that accepts an H⁺ proton from the acid.

So, reactions between acids and bases are H⁺ proton transfer reactions, causing the acid to form its conjugate base and the base to form its conjugated acid by exchanging a proton.

In this case, the reaction between hypoiodous acid and water is:

HOI + H₂O ⇄ OI⁻ + H₃O⁺

where HOI acts as an acid because it donates a potron, while water acts as a base because it accepts the proton donated by HOI.

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The concentration of a substance can be expressed using molarity, molality or percent.

The term concentration has to do with the amount of substance present in solution. Now let us solve the problems individually;

a) Number of moles =  0.850 grams/80 g/mol = 0.011 moles

molarity = 0.011 moles/345 * 10^-3 L = 0.032 M

b) Number of moles =  13.5g /58 g/mol = 0.23 moles

molality = 0.23 moles/250 * 10^-3 Kg = 0.92 m

c) Number of  moles = 16.5 g/128 g/mol = 0.13 moles

molality = 0.13 moles/54.3  * 10^-3 Kg =2.39 m

d) Total mass present =  12 g +  18 g + 25 g + 500 g = 555 g

mass percent of calcium sulfate =  12 g/555 g * 100/1 = 2.2 %

mass percent of sodium nitrate =  18 g/ 555 g  * 100/1 = 3.2 %

mass percent of potassium chloride = 25 g / 555 g  * 100/1 = 4.5%

mass percent of water =  500 g / 555 g  * 100/1 =90.1%

e) Total mass present = 125 g + 1500g = 1625 g

Mass percent of NaCl =  125 g/1625 g * 100/1 = 7.7%

f) Total volume of solution = 15 L +  28 L  = 43 L

percent by volume of acetone = 15 L/43 L * 100/1 =  34.9%

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Answer:

True

Explanation:

Answer:

true

Explanation:

Answer:

Depending on the actual amount of water, it's going to overfill.

Explanation:

If your watershed is already one that has a lot of water and is always filled, it's likely that your wetlands and rivers will start to overfill, causing a form of flooding.

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I hope this helps!

-No one

Answer:

c

Explanation:

the reason is because your a homosiejenenddj

The pH indicators that would be used to determine the unknown substance are :

The pH indicators that can be used to identify the mysterious white powder in the kitchen must be an acid-base indicator such as Litmus or other form of effective pH indicators like methyl orange and Phenol red.

The pH value of the substance as indicated by the acid-base indicators will help to determine what the mysterious white powder is based on the varying pH of the substances resembling the white powder.

Hence we can conclude that The pH indicators that would be used to determine the unknown substance are :Litmus , Methyl orange, Phenol Red.

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False, there are 9 named classes of hazardous materials.

Hazardous materials are substances or chemicals that pose a health hazard, a physical hazard, or harm to the environment.

There are 9 hazardous substances symbols you need to know: flammable, oxidising, explosives, gas under pressure, toxic, serious health hazard, health hazard, corrosive and environmental hazard.

Hence, the statement is false.

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Answer:

The answer is Polar.

Explanation:

Because polar has many unique properties.

Answer:

heat carbunate

Explanation:

thats true im good in here like and heart byebye

Answer:

3) The amount of matter within the system remains the same

5) The cycle has a well-defined starting and stopping point.

Explanation:

A closed system is a system that the boundaries of a system cannot be passed by either matter or energy.

Hence, generalisations can be made based on a closed system and the law of conservation of mass which states that matter can neither be created nor destroyed but can only change form.

Based on the charge on the aluminium ion, 0.9 g of aluminium are deposited by 0.1 F of electricity.

Electrolysis is the decomposition of a substance known as an electrolyte when electric current is passed through it.

The mass and hence moles an electrolyte deposited when current is passed through it depends on the charge on the ion.

Aluminium ion has a charge of +3 and requires 3F of electricity to deposit 1 mole or 27 g of aluminium

0.1 F will discharge = 0.1/3 × 27 g of aluminium

mass of aluminium deposited = 0.9 g of aluminium.

Therefore, 0.9 g of aluminium are deposited by 0.1 F of electricity.

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The molecular formular shows all the atoms in the compound. The molecular formula of the compound is C15H10O5.

The molecular formula is the formula of the compound that shows the total number of atoms in a compound.

We know that;

ΔT = K m i

ΔT = 26.4°C

K = 40.0°C kg/mol

m = ?

i = 1

26.4°C = 40.0°C kg/mol * m * 1

m = 26.4°C/40.0°C kg/mol  = 0.66 m

We know that

m = mass/molar mass ÷ mass of solvent(in Kg)

Let the molar mass be MM

m = 3.044 g/MM ÷ (18 * 10^-3 Kg)

0.66 m =  3.044 g/0.018MM

0.66 m  * 0.018MM =  3.044 g

MM = 3.044 g/0.66 m  * 0.018

MM = 256 g/mol

Now;

Mass of C =  17.80 * 10^-3/44 * 12 = 0.00485 g

Moles of C = 0.00485 g/12 g/mol = 0.0004 moles

Mass of H = 2.08 * 10^-3/18  * 2 = 0.0002 g

Moles of H =  0.0002 g/1 g/mol = 0.0002 moles

Mass of O = [7.40 * 10^-3 - (0.00485 + 0.0002)] = 0.00235 g

Moles of O = 0.00235 g/16 g/mol = 0.000147 moles

Divide through by the lowest number of moles;

C - 0.0004/0.000147  H - 0.0002/0.000147  O - 0.000147 /0.000147

C - 3   H  -  2  O -  1

The empirical formula is C3H2O

So;

[3(12) + 2(1) + 1(16)]n = 256

[36 + 2 + 16]n = 256

n = 5

Molecular formula = C15H10O5

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Answer:

Plant Adaptations is a unique feature a plant has that allows it to live and survive in its own particular habitat (the place that it lives). Desert Plant Adaptations – Plant Adaptation is really a unique have a plant has that enables it to reside and survive in the own particular habitat (the area it lives).

Explanation:

The mass of the sample to methane that contains 3.62×10²⁹ atoms of hydrogen is 4810631.24 g

6.02×10²³ atoms  = 1 mole of Hydrogen

1 mole of Hydrogen = 2 g

Thus,

6.02×10²³ atoms  = 2 g of Hydrogen

Therefore,

3.62×10²⁹ atoms =  (3.62×10²⁹ × 2) / 6.02×10²³

3.62×10²⁹ atoms = 1202657.81 g of Hydrogen

Thus,

4 g of Hydrogen is present in 16 g of methane.

Therefore,

1202657.81 g of Hydrogen will be present in = (1202657.81 × 16) / 4 = 4810631.24 g of methane

Thus, we can conclude that the mass of the sample of methane is 4810631.24 g

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The freezing points of each of the solutions are as follows;

0.100 m K2S -   - 0.558oC

21.5 g of CuCl2 in 4.50 * 102 g water -   -2oC

5.5% NaNO3 by mass (in water)​ -     - 2.6oC

The freezing point is the point at which liquid changes to solid. Let us now look at the freezing point of each solution.

a)

Since;

ΔT = K m i

K = 1.86 oC m-1

m = 0.100 m

i = 3

ΔT =   1.86 oC m-1 * 0.100 m * 3 = 0.558oC

Freezing point = 0oC - 0.558oC =  - 0.558oC

b) Number of moles of CuCl2 = 21.5 g/134.45 g/mol = 0.16 moles

molality = 0.16 moles/0.45 Kg = 0.36 m

ΔT = K m i

ΔT =  1.86 oC m-1 * 0.36 m * 3 = 2oC

Freezing point = 0oC - 2 = -2oC

c) Number of moles of NaNO3 = 5.5g/85 g/mol = 0.065 moles

molality of the solution =  0.065 moles/0.0945 Kg = 0.69 m

ΔT =  1.86 oC m-1 * 0.69 m * 2 = 2.6oC

Freezing point = 0oC - 2.6oC = - 2.6oC

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Answer:

About 0.164 g of glucose.

Explanation:

We can determine the mass of glucose produced given the volume of oxygen gas produced with stoichiometry.

Recall that at STP, a mole of any gas occupies a volume of 22.4 L.

From the reaction, six moles of oxygen gas is produced for every one mole of glucose.

Lastly, the molecular weight of glucose is 180.18 g/mol.

Therefore:
[tex]\displaystyle \begin{aligned} 122\text{ mL O$_2$} & \cdot \frac{1\text{ L O$_2$}}{1000\text{ mL O$_2$}}\cdot \frac{1\text{ mol O$_2$}}{22.4\text{ L O$_2$}} \cdot \frac{1\text{ mol C$_6$H$_{12}$O$_6$}}{6\text{ mol O$_2$}} \cdot \frac{180.18\text{ g C$_6$H$_{12}$O$_6$}}{1\text{ mol C$_6$H$_{12}$O$_6$}} \\ \\ & = 0.164\text{ g C$_6$H$_{12}$O$_6$}} \end{aligned}[/tex]

Therefore, about 0.164 g of glucose is produced.

Answer:

gaseous state.

Explanation:

that's the answer

The ratio of moles of AI(NO3)3 to moles Na2CO3 in the reaction is 2:3

In the reaction 2 moles of AI(NO3)3 reacted with 3 moles Na2CO3 so the ratio of the moles is 2 is to 3 represented as 2:3

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Quartz is not regarded as an example of a modified silicate.

This is defined as a hard, crystalline mineral composed of silica with a tetrahedral shape. Silica is also referred to as Silicon dioxide(SiO₂).

This type of mineral is a naturally occurring crystal and isn't a modified silicate but the rest can be modified using their respective constituents thereby making option D the most appropriate choice.

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So

Moles of Oxygen:-

3 mol of O_2 produces 2 mol SO_2

1 mol of ao_2 produces 2/3=0.6mol So_2

1.396 mol produces 0.8376mol SO_2

Mass of SO_2

Answer:

Explanation:

You have the equation. Now change the 3.4 g H2 to moles. moles = grams/molar mass

3.4 g/2.016 = 1.686 moles.

Now using the coefficients in the balanced equation, convert moles H2O2 to moles H2O.

1.686 moles H2 x (2 moles H2O/2 moles H2O2) = 1.686 x (2/2) = 1.686 x (1/1) = 1.686 moles H2O.

Now you know that 1 mole of water is composed of 6.022 x 10^23 molecules. So

1.686 moles H2O x (6.022 x 10^23 molecules H2O/1 mole H2O) = ?? molecules.