Question

Which of the following statements are true about combustion reactions? (Choose all that apply)
Group of answer choices

reactants are hydrocarbon and oxygen

products won't always be the same

always produce the same two substances

carbon dioxide is a product

water is a product

heat and/or light is produced

methane gas is a product

Flag question: Question 2
Question 210 pts
What is a hydrocarbon?
Group of answer choices

a compound composed of hydrogen and carbon and sometimes oxygen

anything with water

compound composed of helium and carbon

a compound composed of hydrogen and carbon only, never oxygen

Flag question: Question 3
Question 39 pts
Which is NOT a hint for balancing combustion reactions?
Group of answer choices

balancing elements in this order: C, H, O

double the hydrocarbon first

reduce at the end if needed

balance oxygen first

Answer 1

Question 1 — Which statements are true about combustion reactions? (choose all that apply)
- reactants are hydrocarbon and oxygen — True (combustion typically involves a fuel, often a hydrocarbon, reacting with O2)
- products won't always be the same — True (complete combustion gives CO2 and H2O; incomplete can give CO, C (soot), or other products)
- always produce the same two substances — False
- carbon dioxide is a product — True (product of complete hydrocarbon combustion)
- water is a product — True (product of hydrocarbon combustion)
- heat and/or light is produced — True (combustion is exothermic)
- methane gas is a product — False (methane is a fuel, not a general combustion product)

Question 2 — What is a hydrocarbon?
- a compound composed of hydrogen and carbon only, never oxygen — Correct

Question 3 — Which is NOT a hint for balancing combustion reactions?
- balance oxygen first — NOT a helpful hint (usual order: balance C, then H, then O; you may double the hydrocarbon first or reduce coefficients at the end if needed)