Answer:
the specimen has 11460 years old
Explanation:
if the live sample has as initial amount of Yo C14, the dead sample will have 0.25Yo of C14.
the rate of decay of radiactive matter over time is
- Y(t) = Yo * e (( - t * Ln2 ) / T)
∴ Y(t) = 0.25Yo; T = 5730
⇒ 0.25Yo = Yo * e (( - t * Ln2 ) / 5730 )
⇒ 0.25 = e (( - t * Ln2 ) / 5730 )
⇒ Ln(0.25) = ( - t * Ln2 ) / 5730
⇒ - 7943.466 = - t * Ln2
⇒ 7943.466 / Ln2 = t
⇒ t = 11460 year
<u>Answer:</u>
<em>A negative ∆H means that energy is given off from a reaction
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<u>Explanation:</u>
If the reaction has negative ∆H value then the reaction is exothermic
If the reaction has positive ∆H value then the reaction is endothermic
When Heat energy is given in the equation itself
If it is present on the left side it means that heat is absorbed and the reaction is Endothermic
If it is present on the right side it means heat is given off and the reaction is exothermic
Answer:
H2 & F2
Explanation:
A covalent bond is formed when an electron is shared between two atoms. The two electrons of the covalent bond are positioned between the nuclei of the both bonding atoms. The electron pair of the bond may be equidistant from the nucleus of the two atoms or nearer to the nucleus of one of the bonding atoms than the other depending on the relative electro negativities of the both bonding atoms.
For homonuclear covalent bonds, there is no electro negativity difference between the bonding atoms. A single line may be used to indicate the shared electron pair between the two atoms.
Hydrogen and fluorine form homonuclear covalent diatomic compounds in which only a single electron pair is shared between bonding atoms. A single covalent bond is found connecting the two bonding atoms, hence the answer.
<u>125</u> is the total number of neutrons in an atom of 207/82 Pb
207 - 82 = 125
207 represents the mass number of the atom while 87 represent the atomic number. The mass number is usually the sum of the protons and neutrons in the nucleus.
Explanation:
Atoms of elements are usually classified by their proton number. A change in the proton number changes the element. However, the neutron number of an element can differ within a small range giving various isotopes of the element. Some will be stable others will be less stable. The less stable are less common to occur naturally because they decay.
Usually, for smaller atoms, the number of neutrons is more or less similar to the number of protons. However, with larger atoms, there are more neutrons than protons.
Learn More:
For more on atomic and mass numbers check out;
brainly.com/question/1619702
brainly.com/question/13649517
brainly.com/question/11837355
brainly.com/question/2301068
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