Classify the following change as physical or chemical: A match lights when struck.

A. Physical change

B. Chemical change

The planetary model of the solar system has changed over time. Under Aristotle's geocentric model, the sun, stars and planets revolved around the Earth. Later, Copernicus' heliocentric model explained that planets revolved around the sun.

What is the mass of 57ml of water

Which of the following compounds does NOT contain molecules? Question 2 options: CO2 H2 NaCl H2O

Consider just the first sentence of this multistep word problem. Sentence 1: The sum of the ages of a brother and sister is 26. Give an equation that represents this statement using b as the age of the brother and s as the age of the sister.

There is a drought in an area over a long period of time. How could it possibly affect the amount of wildlife that are able to survive in the area.

The specific gravity of iron is 7.87, and the density of water at 4.00 ∘C is 1.00 g/cm3. You can use this information to find the density of iron. Find the volume occupied by 4.50 g of iron.

The volume of a gas is 93 ml when the temperature is 91? c. if the temperature is reduced to 0? c without changing the pressure, what is the new volume of the gas?

15.434 g of kcl (m. m 74.55 g/mol) is dissolved in water up t a total volume of 500.0 mL. the density of this solution is 1.02 g/mL. what is the concentration of he solution in molality

Determine the molar mass of an unknown monoprotic acid to two decimal places if 20.01 ml of a 0.098 m naoh solution were used to titrate 0.215 g of the unknown acid

A diatomic molecule with a triple covalent bond is A. H2 B. N2 C. O2 D. Br2 (P. S. The answer turned out to be B. N2)