At the Bulihan market, a vendor mixes vinegar and baking soda in a bottle. It fizzes and the bottle feels cooler. What are the signs of a chemical reaction here?

An iron gate in Bulihan develops a reddish-brown, flaky coating after years of rain. What kind of change is this?

A tokwa maker in Silang adds vinegar to soy milk, and white curds form and separate from the liquid. What does this show?

A creek in Bulihan turns gray, smells strong, and bubbles after a workshop opened nearby. What best explains this?

A tricycle mechanic in Bulihan sees greenish, crusty buildup on old battery terminals. What caused this?

Blue litmus paper turns red when dipped in kalamansi juice at the Bulihan market. What does this show?

A sari-sari store soap solution turns red litmus blue and feels slippery. What does this indicate?

Irrigation water from a Bulihan creek shows no color change on red or blue litmus paper. What does this mean?

Suka turns blue litmus red, Zonrox turns red litmus blue, and salt water changes neither. How should these be classified?

An antacid tablet dissolved in water turns red litmus blue. Why does this help with hyperacidity?

Sparks fly as a welder joins iron in Bulihan; a dark, brittle coating forms afterward. What type of reaction is this?

In Silang, heating limestone produces apog (calcium oxide) and releases carbon dioxide gas. What type of reaction is this?

An iron nail from a Bulihan hardware store bubbles when soaked in vinegar. What type of reaction is this?

A Silang technician mixes calcium hydroxide with a sulfate fertilizer solution and a white solid forms. What type of reaction is this?

Reaction 1: Iron+Oxygen→Iron oxide. Reaction 2: Calcium carbonate→Calcium oxide+CO2. Reaction 3: Iron+Acetic acid→Iron acetate+H2. Match each to its type.

Tricycles idling at the Bulihan terminal burn gasoline and release exhaust gas. How does this affect the environment?

An old stone church in Silang shows worn, pitted stonework after centuries. What chemically caused this?

In a Silang nursery, plants use CO2 and release O2, while workers breathe in O2 and release CO2. What does this show?

Vog from Taal Volcano carries sulfur dioxide toward Cavite, leaving a film on plant leaves. What causes this film?

An iron floodgate along a Bulihan irrigation canal corrodes quickly due to acidic fertilizer runoff. What reaction explains this?

A BINHS teacher writes 'Vinegar + Baking soda → CO2 + Water + Sodium acetate' in words and formulas. Why use both forms?

LPG (gasul) burns in a Bulihan kitchen, combining with oxygen to form CO2 and water vapor. Which word equation fits?

The word equation for apog-making in Silang is 'Calcium carbonate → Calcium oxide + Carbon dioxide.' Which formula equation matches?

In a Silang nursery, seedlings use CO2 and water plus sunlight to make glucose and release oxygen. Which word equation fits?

A tricycle's iron frame rusts from reacting with oxygen and moisture in Bulihan. Which word equation fits?

In a Bulihan TLE class, LPG burning is shown as 'Fuel+Oxygen→CO2+Water' in words and 'C3H8+5O2→3CO2+4H2O' in formulas. Why two forms?

A tricycle's iron frame in Bulihan rusts from reacting with oxygen and moisture. Which word equation fits?

A magnesium ribbon burns brightly in a lab, forming white magnesium oxide ash. Which word equation fits?

The word equation 'Hydrogen + Oxygen → Water' is given. Which formula equation matches it correctly?

A judge asks what the formula 'H2O2→H2O+O2' shows that the word equation doesn't. What's the best answer?

For a Bulihan science fair project, baking soda and vinegar react inside a sealed, weighed flask. What should the mass be after, and why?

In Silang, heating limestone in an open kiln to make apog leaves a lighter solid. Why doesn't this break conservation of mass?

In 2H2+O2→2H2O, all reactant atoms end up in the water product. What idea does this best show?

A 10g candle burns in a sealed 60g jar; only 7g of candle remains. What's the jar's total mass after, and why?

Steel wool glows and reacts with oxygen inside a sealed, balloon-covered flask. The steel gets heavier but total flask mass stays the same. Why?

Iron reacts with oxygen to form rust: Fe + O2 → Fe2O3. Which equation is correctly balanced?

Propane (C3H8) burns completely: C3H8 + O2 → CO2 + H2O. Which equation is correctly balanced?

Hydrogen and oxygen form water: H2 + O2 → H2O. Which equation is correctly balanced?

Magnesium burns in oxygen: Mg + O2 → MgO. Which equation is correctly balanced?

Methane burns completely: CH4 + O2 → CO2 + H2O. Which equation is correctly balanced?

A Bulihan vendor keeps Silang vegetables cold in an ice box, and they stay fresh longer. Why does cold help?

A tricycle spare part rusts faster outdoors in humid Bulihan air than one kept dry indoors. Why?

A plastics factory uses a catalyst to speed up production without extra heat. What does the catalyst do?

Firefighters use water, foam, or clearing vegetation to control fires. What do these methods have in common?

Smog forms faster on hot, sunny days than cool, cloudy ones, even with the same exhaust levels. Why?

Vinegar and baking soda fizz in a bottle at the Bulihan market, and the bottle feels cooler. What type of reaction is this?

In Silang, adding water to quicklime (calcium oxide) makes the mixture very hot and steamy. What type of reaction is this?

A campfire's burning wood gives off heat and light that people gather around. What type of reaction is this?

An instant cold pack becomes very cold seconds after ammonium nitrate mixes with water. What type of reaction is this?

Photosynthesis absorbs light energy to build glucose; respiration releases energy as glucose breaks down. How should each be classified?