Combined - Science

What is an acid?

A chemical species that increases the concentration of hydrogen ions (H⁺) in an aqueous solution

What is a base?

A chemical species that increases the concentration of hydroxide ions (OH⁻) in an aqueous solution

Negative impact of UV on nail

UVA rays penetrate the skin deeply and can damage skin cells. This may lead to premature aging on the hands. Prolonged exposure, especially with frequent treatments, aLal increases the risk of skin cancer like squamous cell carcinoma.

What are the physical and chemical properties of acids?

Acids have a sour taste, conduct electricity, react with metals to produce hydrogen gas, turn blue litmus red, and have a pH less than 7

What are the physical and chemical properties of bases?

Bases have a bitter taste, slippery feel, conduct electricity, turn red litmus blue, and have a pH greater than 7

What defines a strong acid or base?

Its ability to completely ionise or disassociate in an aqueous solution.

What is a neutralization reaction?

A chemical reaction in which an acid and a base react quantitatively to form water and a salt

What is the carbon cycle?

The biogeochemical cycle through which carbon is exchanged among the atmosphere, hydrosphere, land and living organisms on the Earth.

What is the nitrogen cycle?

The series of processes by which nitrogen and its compounds are interconverted in the environment and in living organisms

What is a longitudinal wave?

A wave in which the particles of the medium oscillate parallel to the direction of wave propagation or energy transfer. In longitudinal waves, compressions and rarefactions occur as the wave travels through the medium.

What is a transverse wave?

A wave in which the particles of the medium oscillate perpendicular to the direction of wave propagation or energy transfer. In longitudinal waves, crests and troughs emerge as the wave travels through the medium.

What is the wave equation? (λ)

Speed of wave = wavelength x frequency

What is the speed of light?

3×10^8

What are mechanical waves?

Mechanical waves represent disturbances that travel require a medium to propogate. Examples include sound waves, water waves, and seismic waves.

Mechanical digestion

The physical breakdown of food into smaller pieces without altering its chemical structure

Chemical digestion

The breakdown of macromolecules into their monomeric units (e.g., proteins into amino acids) through enzymes like amylase, lipase and pepsin.

What are the key organelles of the digestive tract?

Mouth, esophagus, stomach, small intestine, large intestine, anus and rectum, alongside accessory organs like the gallbladder, pancreas and liver

Why is digestion important?

Digestion breaks down complex food molecules into smaller, absorbable units—such as amino acids, simple sugars, and fatty acids—that the body can absorb into the bloodstream. It can use this for energy, growth, repair, and cellular functions.

What is photosynthesis?

The process by which plants synthesise sunlight, water and carbon dioxide to create oxygen and energy in the form of glucose. This is a conversion of light energy to chemical energy.

Chemical formula for photosynthesis

6CO2 + 6H2O = C6H12O6 + 6O2

What is respiration?

The chemical process by which energy is released from glucose. It occurs in all living cells.

Where does respiration take place?

In the mitochondria

Where does photosynthesis take place?

In the chloroplast

Chemical formula for respiration

C6H12O6 + 6O2 = 6CO2 + 6H2O

What is a wave?

A propagating disturbance that transfers energy from one end to another without a net movement of particles

What is the law of reflection?

Angle of incidence is equal to the angle of reflection

What is diffraction?

The bending of waves around the corners of an obstacle

How to calculate time period?

1/f

How to calculate frequency

1/T

How is pH relevant for digestion?

Different enzymes have optimal pH levels for their activity. The stomach's acidic environment (pH 1.5-3.5) is necessary for activating pepsin, an enzyme that digests proteins.

What do enzymes do?

Enzymes speed up chemical reactions by lowering the activation energy needed for the reaction to proceed