Answer:
C. CH4 + 202 – CO2 + 2H20
Explanation:
CH4+O2-CO2+H20
The above equation represents combustion of methane to produce carbon-dioxide and water.
One carbon atom is present on the reactant side as well as on the product side. Four hydrogen atoms are present on the reactant side and two hydrogen atoms on product side. In order to balance this equation, we would multiply water molecule by two. Now there are four atoms of oxygen in the product side but only two on reactant side, so we will multiply oxygen molecule by two on the reactant side. Now the equation is balanced.
The balanced chemical equation is:
CH4+202-CO2+2H2O
This equation obeys the law of conservation of mass as the mass of the reactants is same as that of the products.
Answer:
D. A bicycle rusting.
Explanation:
A. is incorrect because tearing a piece of paper is a physical change, not a chemical change.
B. is incorrect because we are just heating up the object. That only changes how fast the particles are moving and the change in state of matter.
C. is incorrect because we are adding heat to change a state of matter (from solid to liquid) and it is a physical change.
Therefore, only D. is the correct answer. Iron rusts, and when it does, it chemically changes into an iron oxide (rust).
Answer: Enviroment
Explanation: Environmental factors or conditions influences growth, health
The freezing temperature of rain (water) on Earth at sea level in Fahrenheit is 32 F. In Celsius water freezes at 0 C.
