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3 years ago

Which statements describing chemical and nuclear reactions are true?

1 answer:

8 0

Answer is: 2. Chemical reactions involve the rearrangement of electrons and 5. Isotopes of the same element behave differently in a nuclear reaction.

1) The electrons of an atom participates in a chemical reaction.

2) Chemical reactions involve the rearrangement of electrons, because there is transfer, loss, gain and sharing of electrons in chemical reactions.

3) Nuclear reactions can produce new elements, because number of protons and neutrons is changed.

4) Chemical reactions require heat or an input of energy to occur, this is activation energy.

5) Isotopes of the same element behave differently in a nuclear reaction, because isotopes have different number of neutrons, so products of a nuclear reaction is different.

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Mothballs are composed primarily of the hydrocarbon naphthalene (C10H8). When 1.025 g of naphthalene is burned in a bomb calorim

Serggg [28]

Answer:

$\Delta E_{rxn}$ for combustion of naphthalene is -5164 kJ/mol

Explanation:

$\Delta E_{rxn}=C_{calorimeter}\times \Delta T_{calorimeter}$

where, C refers heat capacity and $\Delta T$ refers change in temperature.

Here, $\Delta T_{calorimeter}=(32.33-24.25)^{0}\textrm{C}=8.08^{0}\textrm{C}$

So, $\Delta E_{rxn}=(5.11\frac{kJ}{^{0}\textrm{C}})\times (8.08^{0}\textrm{C})=41.3kJ$

$\Delta E_{rxn}$ is generally expressed in terms of per mole unit of reactant. Also, $\Delta E_{rxn}$ should be negative as it is an exothermic reaction (temperature increases).

Molar mass of naphthalene is 128.17 g/mol

So, 1.025 g of naphthalene = $\frac{1.025}{128.17}moles$ of naphthalene

= 0.007997 moles of naphthalene

$\Delta E_{rxn}=-\frac{41.3kJ}{0.007997mol}=-5164kJ/mol$

5 0

3 years ago

What is the periodic trend in atomic size and electronegativity as you move from left to right on the?

Darya [45]

As you move from left to right on the periodic table, atomic size and electronegativity increase.

(Ionization energy increases from left to right on the periodic table, and electronegativity relates to ionization energy in that the higher the ionization energy, the higher the electronegativity.)

(Atomic radius increases from left to right on the periodic table due to the fact that electrons are gradually being added from left to right, meaning the amount of protons in the nucleus are increasing in order to keep the atom neutral, therefore atomic size/radius increases.)

6 0

3 years ago

The age of water or wine may be determined by measuring its radioactive tritium(3H) content. Tritium, present in a steady state

notsponge [240]

Answer: 29.0 years

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.693}{k}$

$k=\frac{0.693}{12.5years}=0.0554years^{-1}$

b) for decomposition of 80 % of reactant

$t=\frac{2.303}{0.0554}\log\frac{100}{100-80}$

$t=\frac{2.303}{0.0554}\log\frac{100}{20}$

$t=29.0 years$

The age of a suspected vintage wine that is 20 % as radioactive as a freshlybottled specimen is 29.0 years

4 0

3 years ago

state how matter moves through the biosphere. state how energy moves through the biospere. explian each statement using examples

lidiya [134]

<span>Solar energy arrives and is converted into chemical energy by plants which is eaten by animals and converted again and the animal is either eaten by another animal or dies and is broken down by decomposers and the energy is converted back into basic elements for plants to feed off of with the help of solar energy hence the cycle starts again

sorry this is all i know i hope it helps</span>

8 0

3 years ago

For the oxidation-reduction reaction equation given here 4ga+p4 indicate how many electrons are transferred in the formation of

sergij07 [2.7K]

The reaction given is:

4Ga + P4 ---> 4GaP

The oxidation number of the reactants is zero, because they are pure elements.

The P in compounds may have oxidation states 3- or 5-. Gallium may only have oxidation state 3+.

Then, to be neutral in GaP the oxidation states are 3+ for Ga and 3- for P.

And the transference of electrons can be see in this oxidation - reduction equations:

Ga (0) - 3 e- ----> Ga (3+)

P (0) + 3e- ---> P (3-)

So, for one formula unit, 3 electrons have been transfered from each Ga atom to P atom to form one GaP unit.

Answer: 3 electrons.

3 0

3 years ago