BTEC (Business and Technology Education Council) BTEC Applied Science Syllabus

Define atomic (proton) number and mass number.

Atomic number = the number of protons in an atom's nucleus. Mass number = the total number of protons plus neutrons.

How do you calculate the number of neutrons in an atom?

Number of neutrons = mass number $-$ atomic number.

What are isotopes?

Isotopes are atoms of the same element with the same number of protons (same atomic number) but a different number of neutrons (different mass number).

How are elements arranged in the modern periodic table?

In order of increasing atomic (proton) number. Vertical columns are groups (same number of outer electrons), and horizontal rows are periods.

What does the group number of an element in the periodic table tell you?

The group number equals the number of electrons in the outermost shell (for the main groups), which determines the element's chemical properties.

Describe ionic bonding.

Ionic bonding is the transfer of electrons from a metal to a non-metal. The metal forms a positive ion (cation) and the non-metal forms a negative ion (anion); they are held together by strong electrostatic attraction.

Describe covalent bonding.

Covalent bonding is the sharing of one or more pairs of electrons between two non-metal atoms, so each atom gains a full outer shell.

What is metallic bonding?

The attraction between positive metal ions and a 'sea' of delocalised (free) electrons. This explains why metals conduct electricity and are malleable.

Why do ionic compounds conduct electricity when molten or dissolved but not when solid?

When solid, the ions are held in fixed positions and cannot move. When molten or dissolved, the ions are free to move and carry charge, so the compound conducts.

What is the pH range, and what do the values indicate?

The pH scale runs from $0$ to $14$. Below $7$ is acidic, exactly $7$ is neutral, and above $7$ is alkaline (basic). Lower pH = more acidic (more $\ce{H+}$ ions).

Write the general word equation for the reaction of an acid with a metal.

Acid $+$ metal $\to$ salt $+$ hydrogen. For example: $\ce{2HCl + Mg -> MgCl2 + H2}$.

Write the general word equation for the reaction of an acid with a base (neutralisation).

Acid $+$ base $\to$ salt $+$ water. The ionic equation is $\ce{H+ + OH- -> H2O}$.

What products form when an acid reacts with a carbonate?

Acid $+$ carbonate $\to$ salt $+$ water $+$ carbon dioxide. For example: $\ce{2HCl + CaCO3 -> CaCl2 + H2O + CO2}$.

What is a wave, and how do transverse and longitudinal waves differ?

A wave transfers energy without transferring matter. In a transverse wave the oscillations are perpendicular to the direction of energy transfer (e.g. light). In a longitudinal wave the oscillations are parallel (e.g. sound), with compressions and rarefactions.

Define the amplitude, wavelength and frequency of a wave.

Amplitude: maximum displacement from the rest position. Wavelength ($\lambda$): distance between two corresponding points on adjacent waves. Frequency ($f$): the number of waves passing a point per second, measured in hertz ($\text{Hz}$).

State the wave speed equation with units.

$$v = f \lambda$$ where $v$ is wave speed in $\text{m/s}$, $f$ is frequency in $\text{Hz}$, and $\lambda$ is wavelength in $\text{m}$.

List the electromagnetic spectrum in order of increasing frequency.

Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays. (Increasing frequency and energy; decreasing wavelength.)

State the equation linking charge, current and time.

$$Q = I t$$ where $Q$ is charge in coulombs ($\text{C}$), $I$ is current in amperes ($\text{A}$), and $t$ is time in seconds ($\text{s}$).

State Ohm's law as an equation, with units.

$$V = I R$$ where $V$ is potential difference in volts ($\text{V}$), $I$ is current in amperes ($\text{A}$), and $R$ is resistance in ohms ($\Omega$).

Compare how current and potential difference behave in a series circuit.

In a series circuit the current is the same at every point. The total potential difference of the supply is shared between the components.

Compare how current and potential difference behave in a parallel circuit.

In a parallel circuit the potential difference is the same across each branch. The total current is shared (split) between the branches.

State the equation for electrical power in terms of current and voltage.

$$P = I V$$ where $P$ is power in watts ($\text{W}$), $I$ is current in amperes, and $V$ is potential difference in volts.

State the equations for kinetic energy and gravitational potential energy.

Kinetic energy: $$E_k = \frac{1}{2} m v^{2}$$ Gravitational potential energy: $$E_p = m g h$$ where $m$ is mass ($\text{kg}$), $v$ is speed ($\text{m/s}$), $g$ is gravitational field strength ($\approx 9.8\,\text{N/kg}$), and $h$ is height ($\text{m}$).

State the equation linking force, mass and acceleration (Newton's second law).

$$F = m a$$ where $F$ is the resultant force in newtons ($\text{N}$), $m$ is mass in kilograms ($\text{kg}$), and $a$ is acceleration in $\text{m/s}^{2}$.

State the principle of conservation of energy.

Energy cannot be created or destroyed, only transferred (transformed) from one store to another or dissipated. The total energy in a closed system remains constant.

What is the difference between a measuring cylinder and a pipette/burette in terms of accuracy?

A measuring cylinder gives an approximate volume. A pipette (fixed volume) and a burette (variable, readable to $0.05\,\text{cm}^{3}$) are far more accurate and precise, so they are used in titrations.

Why should you read a measurement at eye level at the bottom of the meniscus?

Reading the bottom of the meniscus at eye level avoids parallax error, giving an accurate and consistent volume reading.

What is the purpose of a titration?

A titration accurately measures the volume of one solution needed to exactly react with a known volume of another, used to find an unknown concentration (e.g. of an acid or alkali).

In a titration, what is a 'concordant' set of titres and why is it important?

Concordant titres are results within $0.10\,\text{cm}^{3}$ of each other. They are averaged (ignoring rough/anomalous trials) to give a reliable, precise mean titre.

Give three general laboratory safety rules.

Wear safety goggles (and a lab coat); never eat, drink, or taste chemicals; tie back long hair and tuck in loose clothing near flames; know the location of safety equipment and report all spills/accidents.

Why are repeat readings taken and a mean (average) calculated in experiments?

Repeats and averaging reduce the effect of random errors, identify anomalous results (outliers to discard), and improve the reliability and accuracy of the data.