SOF NSO flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Reactivity series order

A ranking of metals by reactivity: potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, hydrogen, copper, mercury, silver, gold. Metals above hydrogen displace it from dilute acids.

Malleability and ductility

Malleability is the ability to be hammered into thin sheets; ductility is the ability to be drawn into wires. Both are typical metal properties, while non-metals are generally brittle.

Amphoteric oxide example

Aluminium oxide and zinc oxide react with both acids and bases to form salts and water, so they are called amphoteric oxides. Most metal oxides are only basic.

Ionic versus covalent bond

An ionic bond forms when a metal transfers electrons to a non-metal, creating oppositely charged ions. A covalent bond forms when non-metal atoms share electron pairs, as in water or methane.

Catenation and tetravalency

Catenation is carbon's ability to bond with itself forming long chains and rings; tetravalency means carbon forms four bonds. Together they explain carbon's huge number of compounds.

Homologous series

A family of organic compounds with the same functional group and general formula, where successive members differ by one CH2 unit (14 u). Members show gradually changing physical properties.

Ethanoic acid test

Ethanoic acid reacts with sodium hydrogen carbonate to release carbon dioxide with brisk effervescence, turning limewater milky. Ethanol does not give this test, so it distinguishes the two.

Ohm's law

At constant temperature, the current through a conductor is directly proportional to the potential difference across it, so V = IR. Resistance R is measured in ohms.

Series versus parallel resistance

In series, resistances add directly and the same current flows through each. In parallel, the reciprocal of total resistance is the sum of reciprocals, and voltage is the same across each branch.

Electric power formulas

Power equals voltage times current, P = VI, and also P = I squared R and P = V squared divided by R. Commercial energy is billed in kilowatt-hours, where 1 kWh equals 3.6 million joules.

Right-hand thumb rule

If you hold a current-carrying straight conductor in your right hand with the thumb pointing along the current, your curled fingers give the direction of the magnetic field around it.

Solenoid magnetic field

A current-carrying solenoid produces a magnetic field pattern similar to a bar magnet, with north and south poles at its ends. Inserting a soft-iron core makes it a strong electromagnet.

Reflex arc components

The pathway of a reflex action: receptor, sensory neuron, spinal cord relay, motor neuron, and effector muscle or gland. It allows a fast response without waiting for the brain.

Insulin and blood glucose

Insulin is a hormone secreted by the pancreas that lowers blood glucose by promoting its uptake and storage as glycogen. Deficiency of insulin causes diabetes mellitus.

Fertilization site in humans

In humans, fertilization occurs in the fallopian tube when a sperm fuses with the ovum. The resulting zygote divides and implants in the uterus wall, where the placenta later forms.

Asexual reproduction types

Asexual reproduction produces genetically identical offspring from one parent. Examples include binary fission in Amoeba, budding in Hydra and yeast, fragmentation in Spirogyra, and regeneration in Planaria.

Opposite letters sum to 27

In the English alphabet, a letter's opposite is found by subtracting its position from 27. For example, C is 3, so its opposite is 24, which is X.

Arithmetic series rule

In a number series, subtract consecutive terms. If the difference is constant, the series is arithmetic; if the difference itself changes in a pattern, extend that pattern to find the next term.

Coding by letter shift

In shift coding, each letter moves a fixed number of places forward or backward in the alphabet. Test the same shift on every given pair before applying it to the unknown word.

Blood relation tree method

Draw a family tree using symbols for male and female, then link generations with lines. Read each phrase carefully, since 'only son of my mother' refers to the speaker himself.

Direction displacement rule

For direction puzzles, sketch each move on a compass. When the final two legs are perpendicular, the shortest distance from start to finish is found using the Pythagorean theorem.

Syllogism validity test

A conclusion is valid only if it holds in every possible Venn diagram consistent with the statements. A conclusion that fails in even one arrangement does not follow.

Ranking total formula

When a person's rank from the left and from the right are both known, the total number of people equals left rank plus right rank minus one, because that person is counted twice.

Odd-one-out grouping

Identify a property shared by most items, such as being prime, a perfect square, or a multiple of a number. The item that lacks that property is the odd one out.

Gas identification in reactions

Hydrogen from acid plus metal burns with a pop sound. Carbon dioxide from acid plus carbonate turns limewater milky. The gas observed identifies the reactant class.

Displacement reaction condition

A metal displaces another from its salt solution only if it is more reactive, that is, higher in the reactivity series. Otherwise no reaction occurs, and the mixture stays unchanged.

Parallel circuit current effect

Adding a resistor in parallel decreases total resistance and increases the current drawn from a fixed-voltage supply. Adding in series increases resistance and decreases the current.

Heating effect of current

The heat produced in a resistor is H = I squared R t. Doubling the current quadruples the heat for the same resistance and time, which is why overloads are dangerous.

Electromagnet strength factors

Electromagnet strength increases with more turns of wire, larger current, and a soft-iron core. Reversing the current direction reverses the poles but does not change the strength.

Unsaturation test

Unsaturated hydrocarbons such as alkenes and alkynes decolourize bromine water, while saturated hydrocarbons like alkanes do not. This test distinguishes the two classes.

Percentage change formula

Percentage change equals the new value minus the old value, divided by the old value, multiplied by 100. A negative result indicates a decrease rather than an increase.

Reflex versus voluntary action

Reflex actions are rapid, involuntary, and mediated by the spinal cord. Voluntary actions are controlled by the brain and are slower, while hormonal responses are slower still but longer lasting.