A sample of uranium absorbs 27.16 kJ of energy and changes temperature by 347.6 C. If 27.17 J/(1C * 1 mole) for uranium, the how many mole of U are in the sample?

Answer:

thx for the points

Explanation:

no need brainliest

Answer:

Calculating Atomic Mass

Change each percent abundance into decimal form by dividing by 100. Multiply this value by the atomic mass of that isotope. Add together for each isotope to get the average atomic mass.

Explanation:

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Answer:

The color or hue of light depends on its wavelength, the distance between the peaks of its waves. The brightness of light is related to intensity or the amount of light an object emits or reflects. Brightness depends on light wave amplitude, the height of light waves.

Explanation:

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Answer:

3.08x10^25

Explanation:

Divide the mass in grams by the molar mass of nitrogen (14.0067), then multiply the result by Avogadro's number (6.022x10^23). Then round to the correct amount of significant figures.

Answer:

fractional distillation

Explanation:

Answer:

F=ma

Explanation:

F=m×a

according to that F÷m=a and also F ÷a=m

Answer:

Synthesis

Explanation:

Trust me on this :)

Answer:

Elements are pure substances which are composed of only one type of atom. Compound are substances which are formed by two or more different types of elements that are united chemically in fixed proportions.

Answer:

Explanation:

Combination of oxidation and reduction reactions.

Where there is oxidation, there is reduction too.

Answer:

If each side of the equation has the same number of atoms of a given element, that element is balanced. If all elements are balanced, the equation is balanced.

Answer:

50g iron comprises 5.376 × 1023 atoms.

Explanation:

Answer:

The energy levels or electron shells of an atom.

Answer:

Each ring represents a different energy level for the electrons. Each ring has a maximum number of electrons that it can hold. The first (inner) ring can only hold two electrons, the second level can hold eight, the third can hold 18 and the fourth holds 32.

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Answer:

Explanation:

Record the letters in your triangle from left to right A MAGNESIUM CHLORATE B MAGNESIUM SULFATE C MAGNESIUM HYPOCHLORIDE D MAGANESE PERCHLORATE E MN C10 F MGMNO G MANGANESE CHLORIDE

Answer:

Mitochondria

Explanation:

Mitochondria is the powerhouse of the cell, convert sustenance into energy, fueling the cell's activities. In addition to power, mitochondria also produce reactive oxygen

Answer:

Cathode rays consist mainly of electrons, they ionize substance, this leads to reduction. Any ions produced are collect by an ion trap in the tube therefore anything the beam of electrons hits is going to gain electrons.

This problem provides information about the decomposition of copper(II) nitrate to copper(II) oxide and dinitrogen monoxide; for example, it is endothermic, the enthalpies of formation and the chemical reaction, as well as copper (II) sulfate which when dissolved in water, exhibits a temperature decrease:

[tex]2Cu(NO_3)_2(s) \rightarrow 2CuO(s) + 4NO_2(g) + O_2(g)[/tex]

First of all, we can draw the reaction pathway as shown on the attached figure, by taking into account the positive enthalpy change as it is endothermic, so that the products turn out with higher energy than the reactants, for it to be positive. In addition, keep in mind that top point is the activation energy the reaction needs to take place.

Next, we calculate the enthalpy change for this reaction by using the general formula which subtracts the enthalpy of formation of products and reactants with each species' correct stoichiometric coefficient:

[tex]\Delta H=2\Delta _fH_{CuO}+4\Delta _fH_{NO_2}+\Delta _fH_{O_2}-2\Delta _fH_{Cu(NO_3)_2}[/tex]

So we plug in the given enthalpies of formation:

[tex]\Delta H=2(-157.3)+4(33.2)+(0)-2(-302.9)=424.0 kJ/mol[/tex]

Finally, we go over the calorimetry experiment, whereby the total heat absorbed by the copper(II) sulfate is calculated via the general heat equation, which includes the heat loss from the solution of water and the salt:

[tex]Q_{rxn}=-mC_w\Delta T\\\\Q_{rxn}=-(100+25)g*4.18\frac{J}{g\°C}*-2.9\°C=1515.25J[/tex]

By dividing the previous answer by the moles of salt:

[tex]n=25.0g*\frac{1mol}{249.7g}=0.100mol[/tex]

We can obtain the enthalpy change of solution of the copper salt:

[tex]\Delta _{dissolution}H=\frac{1,515.25J}{0.100mol} \\\\\Delta _{dissolution}H=15,134J/mol=15.1kJ/mol[/tex]

To conclude, it is important to note that one possible source of error is we are assuming the solution has the same specific heat to that of water and that is not necessarily true. Also, we are neglecting any heat transfer to and from the surroundings despite the polystyrene beaker is considered a heat isolator, which means the results cannot necesarilly be accurate and the enthalpy change could have turned out higher or lower in a rigoruous experiment.

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Answer:

-1

Explanation:

electrons are negative

Answer:

Explanation:

how many grams and moles of gold are present in 8.09 x 10^28 atoms of gold?

there are 6.02 x 10^23 molecules or atoms in 1 mole

of a compound or element

8.09 x 10^28 /(6.02 x 10^23) = 1.34 x 10^5 moles of Au

1 mole of gold (see periodic table for #79) 197 g

so 1.34 x 10^5 moles of Au weigh

197 x 1.34 x 10^5 = 2.64 x 10^7 g

your little gold treasure is worth

Gold Price Per Gram $59.87 x 2.64 x 10^7=

$$$$ 1.58 x 10^9

=$ 1,580,000,000

In this exercise we want to calculate the amount of moles, so this is going to be:

[tex](4.6)(10^{-3}) \ mols \ CO_2[/tex]

Knowing that Henry's law is given by:

[tex]C = KHP[/tex]

Where constants are given by:

Before we can find the concentration of CO2 (and hence the moles of CO2), we first need to find its partial pressure.  We look up the vapor pressure of water at 25º and find it to be 0.03 atm.  Since the total pressure is equal to 0.1 atm, this mean the partial pressure of:

[tex]CO_2 = 0.1 \ atm - 0.03 \ atm = 0.07 \ atm[/tex]

Now using Henry's law, we find the concentration:

[tex]C = (0.033)*( 0.07) = (2.31)*(10^{-3})[/tex]

Converting to moles of CO2, we have:

[tex](2.31)*(10^{-3})*( 2) = (4.6)*(10^{-3})[/tex]

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Answer:

the body can losse heat through Radiation,since Radiation does not involve the direct contact of two mediums

Answer:

I am using an example for this in this table it works for any other compound as well.

Answer:

The answer is B.

Explanation:

the force multiplied by the time objects are in contact

Answer: 1.7 km = [1700]m

1.7 × 10^3

Explanation:

Answer:

1700 meters

Explanation: hope it helps.

Answer:

I think it's 2.50M IM NOT SURE THOUGH SO I RECOMMEND WAITING FOR ANOTHER ANSWER

An ionic bond is formed through the transfer of one or more valence electrons, typically from a metal to a non-metal, which produces a cation and an anion that are bound together by an attractive electrostatic force.

Answer:

Group 17

Explanation:

Group 16 of nonmetals will react with alkaline earth metals to form a compound in a 1 : 1 ratio. Therefore, option (b) is correct.

Alkaline earth metals or Group 2 includes six elements which are Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).

This group contains smooth, silver metals with a less metallic character than group 1.  All alkaline earth metals have two valence electrons, giving a valency of 2. These metals easily lose electrons to form compounds via ionic bonds and become more stable.

The valency of calcium is 2 and the valency of the elements of group 16 is also 2. Therefore they can combine 1 : 1 ratio to form a neutral compound.

Ca²⁺    +   O²⁻   →  CaO

Therefore, the nonmetals of group 16 will react with alkaline earth metal.

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Answer:

elements with low first ionization energies and positive or slightly negative electron affinities generally form cations.

hope it is helpful:)