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2 years ago

How do knowing the half-life of carbon 14 can tell scientists the absolute age of a rock sample

1 answer:

7 0

Carbon 14 dating makes some assumptions that are not exactly true, but likely close enough for most purposes. 1 that the ratio of carbon 13 to carbon 14 in Earth's atmosphere has not changed over the last million years. 2 that living things give zero preference to carbon 13 over carbon 14.
3 Carbon 14 dating is often unreliable for rocks which have low carbon content, such as quartz, and some other assumptions.

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What's the formula of mercury (I) dioxonitrate III

steposvetlana [31]

<h2>Answer:</h2>

<h2>Explanation:</h2>

<h3>Formula of mercury ( 1 ) dioxonitrate 111 is Hg2 ( NO2 )2//</h3>

7 0

2 years ago

The standard molar heat of fusion of ice is 6020 j/mol. calculate q, w, and ∆e for melting 1.00 mol of ice at 0◦c and 1.00 atm p

zysi [14]

Answer : q = 6020 J, w = -6020 J, Δe = 0

Solution : Given,

Molar heat of fusion of ice = 6020 J/mole

Number of moles = 1 mole

Pressure = 1 atm

Molar heat of fusion : It is defined as the amount of energy required to melt 1 mole of a substance at its melting point. There is no temperature change.

The relation between heat and molar heat of fusion is,

$q=\Delta H_{fusion}(\frac{Mass}{\text{ Molar mass}})$ (in terms of mass)

or, $q=\Delta H_{fusion}\times Moles$ (in terms of moles)

Now we have to calculate the value of q.

$q=6020J/mole\times 1Mole=6020J$

When temperature is constant then the system behaves isothermally and Δe is a temperature dependent variable.

So, the value of $\Delta e=0$

Now we have to calculate the value of w.

Formula used : $\Delta e=q+w$

where, q is heat required, w is work done and $\Delta e$ is internal energy.

Now put all the given values in above formula, we get

$0=6020J+w$

w = -6020 J

Therefore, q = 6020 J, w = -6020 J, Δe = 0

3 0

3 years ago

Functional groups create active sites in molecules. The polar part of a molecule that can hydrogen bond to water is said be hydr

VMariaS [17]

Answer:

Polar/Hydrophilic

Explanation:

Fluorine, Nitrogen and Oxygen are strong electronegative atoms and by definition, Electronegativity is the amount of pull or the high affinity of an atom to electrons.

Polar bond occurs when there is a high difference between the electronegativity value of both atoms that take part in the bond.

A polar molecule has a net dipole from the distribution of its positive and negayive charges. Hydrophobic and Hydrophilic (in chemistry, Polar) are terms dependent on the overall distribution of charge in its molecule.

Therefore, bonds between C-N, C-O and C-Cl are polar covalent bonds a d this is because of the jigh electronegativity possessed by Nitrogen, Oxygen and Chlorine.

5 0

2 years ago

1. A sample of polystyrene is found to have a number-average molar mass of 89,440 g mol−1 . Neglecting contributions from end gr

Snowcat [4.5K]

Answer:

The weight-average molar mass of polystyrene is 134,160 g/mol.

Explanation:

Molar mass of the monomer styrene , $C_8H_8$ , M=104 g/mol

Given , number average molar mass of the polymer , M'= 89,440 g/mol

Degree of polymerization = n

$n=\frac{M'}{M}=\frac{89,440 g/mol}{104 g/mol}=860$

The weight-average molar mass = $M_{avg}=?$

Molar mass dispersity is ratio of weight-average molar mass to the number average molar mass of the polymer.

$\text{Molar mass dispersity}=\frac{M_{avg}}{M'}$

$1.5=\frac{M_{avg}}{89,440 g/mol}$

$M_{avg}=89,440 g/mol\times 1.5 = 134,160 g/mol$

The weight-average molar mass of polystyrene is 134,160 g/mol.

8 0

2 years ago

What type of bond is this combination likely to form

kari74 [83]

Answer:

A combination is certainly possible, but you should not take formal charges so literally

Normally, when a covalent bond is found, the two atoms both bring in one electron. As you identify correctly, in the case of nitric acid that would not be possible completely. If you draw the different possible resonance structures, the most likely structure has a single bond between the nitrogen and an oxygen where the oxygen has 3 lone pairs and both electrons in the bond are donated by the nitrogen. This makes the nitrogen "positive" and that oxygen "negative", but in fact the electrons move more freely in the molecule and charges are more distributed. You will not be able to find "the negatively charged" oxygen atom.

Explanation:

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4 0

2 years ago