Isotopes and relative atomic mass

Chemia IBPaper 1A, maj 2026, TZ2wzorowane1 pktzamkniętełatwe (szac.)

Zadanie 2

Bromine (A_r = 79.90) consists of two isotopes, $\ce{^{79}Br}$ and $\ce{^{81}Br}$. What is the relative abundance of $\ce{^{81}Br}$? A. 10 % B. 45 % C. 55 % D. 90 %

Chemia IBPaper 2, maj 2026, TZ3wzorowane3 pktobliczenioweśrednie (szac.)

Zadanie 3a

Silver has two stable and abundant isotopes. Its relative atomic mass is 107.87. (i) Determine the percent abundance of each isotope, showing your working. (ii) State the number of protons, neutrons and electrons in $\ce{^{109}Ag+}$.

• Tabela do uzupełnienia

Chemia IBPaper 1A, maj 2025, TZ2wzorowane1 pktzamkniętełatwe (szac.)

Zadanie 2

Which property is the same for ammonia molecules containing deuterium, ND₃, and ordinary ammonia molecules, NH₃? A. Molar mass B. Molecular geometry C. Density of the gas at STP D. Rate of diffusion

Chemia IBPaper 2, maj 2025, TZ2wzorowane5 pktobliczenioweśrednie (szac.)

Zadanie 2a

Naturally occurring gallium consists of two isotopes: 60 % of the atoms contain 38 neutrons and the remaining 40 % contain 40 neutrons. (i) Use section 7 of the data booklet to deduce the nuclear symbol of the heavier isotope. (ii) Calculate the relative…

Chemia IBPaper 2, listopad 2025, TZ3wzorowane1 pktotwartełatwe (szac.)

Zadanie 5a

Contrast the two isotopes in terms of atomic structure.

Chemia IBPaper 2, listopad 2025, TZ3wzorowane2 pktobliczenioweśrednie (szac.)

Zadanie 5b

Calculate the relative atomic mass of chlorine from the sample, giving your answer to two decimal places.

Chemia IBPaper 1A, specimen 2025wzorowane1 pktzamkniętełatwe (szac.)

Zadanie 2

At 25 °C the density of heavy water, $\ce{^{2}H2O(l)}$, is 1.11 g cm⁻³, while the density of ordinary water, $\ce{^{1}H2O(l)}$, is 1.00 g cm⁻³. Which statement explains this difference? A. Each $\ce{^{2}H}$ nucleus contains one…

Chemia IBPaper 1, listopad 2024wzorowane1 pktzamknięteśrednie (szac.)

Zadanie 5

A sample of element X consists of two isotopes. Their mass numbers and relative abundances are given in the table. What is the relative atomic mass of X? A. 69.0 B. 69.8 C. 70.0 D. 70.2

• Tabela do uzupełnienia

Chemia IBPaper 2, maj 2023, TZ2wzorowane2 pktobliczeniowełatwe (szac.)

Zadanie 4d

Neon has three naturally occurring isotopes, $\ce{^{20}Ne}$, $\ce{^{21}Ne}$ and $\ce{^{22}Ne}$. A sample of neon contains 90.2 % of $\ce{^{20}Ne}$, 0.3 % of $\ce{^{21}Ne}$ and 9.5 % of $\ce{^{22}Ne}$. Calculate the relative atomic mass of this sample, giving…

Chemia IBPaper 2, listopad 2023, TZ1wzorowane4 pktobliczenioweśrednie (szac.)

Zadanie 4c

Naturally occurring sulfur is a mixture of several isotopes. A sample was enriched in $\ce{^{34}_{16}S}$, giving the following composition: (i) Calculate the relative atomic mass of the enriched sample to two decimal places. (ii) The abundance of…

• Tabela do uzupełnienia

Chemia IBPaper 2, listopad 2023, TZ2wzorowane4 pktobliczenioweśrednie (szac.)

Zadanie 4c

Iron has a number of natural isotopes. A sample of iron was enriched in $\ce{^{58}Fe}$ to produce a mixture with the following composition: (i) Calculate the relative atomic mass of the enriched sample, giving your answer to two decimal places. (ii) Natural…

• Tabela do uzupełnienia

Chemia IBPaper 1, listopad 2023, TZ1wzorowane1 pktzamknięteśrednie (szac.)

Zadanie 5

Thallium (A_r = 204.38) consists of two stable isotopes, $\ce{^{203}Tl}$ and $\ce{^{205}Tl}$. What is the relative abundance of $\ce{^{205}Tl}$? A. 31 % B. 38 % C. 62 % D. 69 %

Chemia IBPaper 1, listopad 2023, TZ2wzorowane1 pktzamknięteśrednie (szac.)

Zadanie 5

Naturally occurring bromine has A_r = 79.90 and contains only the isotopes ⁷⁹Br and ⁸¹Br. What percentage of the atoms are ⁸¹Br? A. 10 % B. 45 % C. 55 % D. 90 %

Chemia IBPaper 2, maj 2022, TZ1wzorowane3 pktotwarteśrednie (szac.)

Zadanie 1e

Most oxide ions are $\ce{^{16}O^2-}$. (i) State the number of protons, neutrons and electrons in this ion. (ii) Some oxide ions are $\ce{^{18}O^2-}$. State the term that describes the relationship between $\ce{^{16}O^2-}$ and $\ce{^{18}O^2-}$. (iii) The…

Chemia IBPaper 2, maj 2022, TZ1wzorowane2 pktotwartełatwe (szac.)

Zadanie 1f

Atoms were once thought to be the smallest particles of matter, impossible to divide. Suggest two pieces of evidence that show an atom has an internal structure.

Chemia IBPaper 1, maj 2022, TZ1wzorowane1 pktzamknięteśrednie (szac.)

Zadanie 5

Bromine has two naturally occurring isotopes, $\ce{^{79}Br}$ and $\ce{^{81}Br}$. The relative atomic mass of bromine is 79.90. What is the approximate percentage abundance of $\ce{^{81}Br}$? A. 25 % B. 45 % C. 55 % D. 75 %

Chemia IBPaper 1, maj 2022, TZ2wzorowane1 pktzamkniętełatwe (szac.)

Zadanie 6

A sample of an element contains two isotopes. The table shows their mass numbers and their abundances. Which value is the relative atomic mass of the element? A. 40 B. 41 C. 42 D. 44

• Tabela do uzupełnienia

Chemia IBPaper 2, listopad 2022wzorowane1 pktobliczeniowełatwe (szac.)

Zadanie 3b

Silver occurs as two stable isotopes. Their masses and abundances are given in the table. Show how a relative atomic mass of silver of 107.96 can be obtained from these data.

• Tabela do uzupełnienia

Chemia IBPaper 1, listopad 2022wzorowane1 pktzamknięteśrednie (szac.)

Zadanie 6

Boron has two naturally occurring isotopes. A sample contains 20.0 % boron-10 ($\ce{^{10}B}$) and 80.0 % boron-11 ($\ce{^{11}B}$). What is the relative atomic mass of boron in this sample? A. 10.2 B. 10.5 C. 10.8 D. 11.0