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2 years ago

All isotopes of a given element must have the same

2 answers:

7 0

Isotopes of any given element all contain the same number of protons, so they have the same atomic number (for example, the atomic number of helium is always 2). Isotopes of a given element contain different numbers of neutrons, therefore, different isotopes have different mass numbers.

mafiozo [28]2 years ago

5 0

Answer:

number of protons

Explanation:

Isotopes of any given element all contain the same number of protons, so they have the same atomic number

e.g: the atomic number of helium is always 2.

Isotopes of a given element contain different numbers of neutrons, therefore, different isotopes have different mass numbers.

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After 17.1 thousand years, what percentage of the original carbon-14 would be left in an organism’s remains? After 17.1 thousand

hram777 [196]

Answer:

12.5%

Explanation:

Initial percentage of carbon 14 = 100%

Final percentage = ?

Time passed = 17.1 * 1000 years = 17100 years

Half life of carbon 14 = 5,730 years.

So how many Half lives are in 17100 years?

Number of Half lives = Time passed / Half life = 3.18 ≈ 3

First Half life;

100% --> 50%

Second Half life;

50% --> 25%

Third Half life ;

25% --> 12.5%

6 0

2 years ago

A reaction that involves the transfer of electrons from one molecule to another is referred to as

shepuryov [24]

its a redox reaction.

3 0

2 years ago

What is the definition of economic value

shepuryov [24]

Answer:

Economic value can be described as a measure of the benefit from a good or service to an economic agent. It is typically measured in units of currency. Another interpretation is that economic value represents the maximum amount of money an agent is willing and able to pay for a good or service.

Explanation:

4 0

3 years ago

At 85°C, the vapor pressure of A is 566 torr and that of B is 250 torr. Calculate the composition of a mixture of A and B that b

Phantasy [73]

Answer:

Composition of the mixture:

$x_{A} =0.652=65.2$ %

$x_{B} =0.348=34.8$ %

Composition of the vapor mixture:

$y_{A} =0.809=80.9$ %

$y_{B} =0.191=19.1$ %

Explanation:

If the ideal solution model is assumed, and the vapor phase is modeled as an ideal gas, the vapor pressure of a binary mixture with $x_{A}$ and $x_{B}$ molar fractions can be calculated as:

$P_{vap}=x_{A}P_{A}+x_{B}P_{B}$

Where $P_{A}$ and $P_{B}$ are the vapor pressures of the pure compounds. A substance boils when its vapor pressure is equal to the pressure under it is; so it boils when $P_{vap}=P$ . When the pressure is 0.60 atm, the vapor pressure has to be the same if the mixture is boiling, so:

$0.60*760=P_{vap}=x_{A}P_{A}+x_{B}P_{B}\\456=x_{A}P_{A}+(1-x_{A})P_{B}\\456=x_{A}*(P_{A}-P_{B})+P_{B}\\\frac{456-P_{B}}{P_{A}-P_{B}}=x_{A}\\\\\frac{456-250}{566-250}=x_{A}=0.652$

With the same assumptions, the vapor mixture may obey to the equation:

$x_{A}P_{A}=y_{A}P$ , where P is the total pressure and y is the fraction in the vapor phase, so:

$y_{A} =\frac{x_{A}P_{A}}{P}=\frac{0.652*566}{456} =0.809=80.9$ %

The fractions of B can be calculated according to the fact that the sum of the molar fractions is equal to 1.

7 0

2 years ago

Silver has two naturally isotopes and has an atomic mass of 107.868 amu. One isotope is Ag-109 isotope (108.905 amu) and has a n

Triss [41]

Answer: 106.905

Explanation: If there are only 2 isotopes, and 1 of them is 48.16%, the second must, by default, be (100 - 48.16%) = 51.84% The final, averaged, atomic mass is 107.868. This is made up of each isotope's atomic mass times the percentage of that isotope in the total sample. The weighted value of the known isotope (109) plus that of the unknown must come to the observed value of 107.868 amu. (107.868 - 52.45 = 55.42). Divide that by the % for that isotope (55.42/0.5184) = 106.90 amu for the second isotope.

Atomic Mass % of Sample Weighted Value

108.905 48.16% 52.45

X 51.84% 55.42

107.87

X = (55.42/0.5184) = 106.90 amu

5 0

2 years ago