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3 years ago

An atom has 8 protons, 8 neutrons, and 8 electrons. another isotope of the same element might have

Chemistry

2 answers:

shutvik [7]3 years ago

7 0

Answer:It might have 10 neutrons

Reason: This is because an isotope of the same element must have the same number of electrons and protons so it can be assumed that the amount of neutrons can be changed.

Grace [21]3 years ago

3 0

Isotopes are atoms of the same element that have the same number of protons and electrons but different number of neutrons.
Masses of atoms are the sum of protons and neutrons. Therefore when the number of neutrons change but protons are the same, then the masses of the atoms change.
isotope 1 has 8 protons , 8 electrons and 8 neutrons.
isotope 2 has 8 protons, 8 electrons and 10 neutrons

mass of isotope 1 is 16
and mass of isotope 2 is 18

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Before a bond breaks in a chemical reaction, what happens

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They have to form a chemical bond in order to brake them down first

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3 years ago

Write the balanced equation for the reaction of aqueous Pb ( ClO 3 ) 2 Pb(ClO3)2 with aqueous NaI . NaI. Include phases. chemica

FinnZ [79.3K]

<u>Answer:</u> The mass of precipitate (lead (II) iodide) that will form is 119.89 grams

<u>Explanation:</u>

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of NaI solution = 0.130 M

Volume of solution = 0.400 L

Putting values in above equation, we get:

$0.130M=\frac{\text{Moles of NaI}}{0.400L}\\\\\text{Moles of NaI}=(0.130mol/L\times 0.400L)=0.52mol$

The balanced chemical equation for the reaction of lead chlorate and sodium iodide follows:

$Pb(ClO_3)_2(aq.)+2NaI(aq.)\rightarrow PbI_2(s)+2NaClO_3(aq.)$

The precipitate (insoluble salt) formed is lead (II) iodide

By Stoichiometry of the reaction:

2 moles of NaI produces 1 mole of lead (II) iodide

So, 0.52 moles of NaI will produce = $\frac{1}{2}\times 0.52=0.26mol$ of lead (II) iodide

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of lead (II) iodide = 0.26 moles

Molar mass of lead (II) iodide = 461.1 g/mol

Putting values in above equation, we get:

$0.26mol=\frac{\text{Mass of lead (II) iodide}}{461.1g/mol}\\\\\text{Mass of lead (II) iodide}=(0.26mol\times 461.1g/mol)=119.89g$

Hence, the mass of precipitate (lead (II) iodide) that will form is 119.89 grams

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3 years ago

How much energy would be released if 450.0 g of the substance completely reacted with oxygen?

SOVA2 [1]

Answer:

1.1853 kJ

Explanation:

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3 years ago

A useful single-displacement reaction involves thermite, which is a

Licemer1 [7]

The reaction of iron (III) oxide and aluminum is initiated by heat released from a small amount "starter mixture". This reaction is an oxidation-reduction reaction, a single replacement reaction, producing great quantities of heat (flame and sparks) and a stream of molten iron and aluminum oxide which pours out of a hole in the bottom of the pot into sand.

The balanced chemical equation for this reaction is:

2 Al(s) + Fe2O3(s) --> 2Fe(s) + Al2O3(s) + 850 kJ/mol

Curriculum Notes
This chemical reaction can be used to demonstrate an exothermic reaction, a single replacement or oxidation-reduction reaction, and the connection between ∆H calculated for this reaction using heats of formation and Hess' Law and calculating ∆H for this reaction using qrxn = mc∆T and the moles of limiting reactant. This reaction also illustrates the role of activation energy in a chemical reaction. The thermite mixture must be raised to a high temperature before it will react.

To determine how much thermal energy is released in this reaction, heats of formation values and Hess' Law can be used.

By definition, the deltaHfo of an element in its standard state is zero.

2 Al(s) + Fe2O3(s) --> 2Fe (s) + Al2O3 (s)

The deltaH for this reaction is the sum of the deltaHfo's of the products - the sum of the deltaHfo's of the reactants (multiplying each by their stoichiometric coefficient in the balanced reaction equation), i.e.:

deltaHorxn = (1 mol)(deltaHfoAl2O3) + (2 mol)(deltaHfoFe) - (1 mol)(deltaHfoFe2O3) - (2 mol)(deltaHfoAl)

deltaHorxn = (1 mol)(-1,669.8 kJ/mol) + (2 mol)(0) - (1 mol)(-822.2 kJ/mol) - (2mol)(0 kJ/mol)

deltaHorxn = -847.6 kJ

The melting point of iron is 1530°C (or 2790°F).
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2 years ago

A sample of polonium-210 has an initial mass of 390 milligrams (mg). If the half-life of polonium-210 is 36 days, how many mg of

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Answer: D. 48.75

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2 years ago

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