7. Halfway through a cross country meet, a

runner's speed is 4 m/s. In the last stretch,

she increases her speed to 7 m/s. What is

her change in speed

What is the mass percent of nitrogen in ammonium carbonate, (NH4) 2CO3?

Explain why calcium metal after reacting with water starts floating on its surface. Write the chemical equation for this reaction. Name one more metal that starts floating after sometime then floats with water.

The atomic mass of an element on the Periodic Table is the weighted average mass of the isotopes of that element. True False

4. Identify the compound with covalent bonds. A) CH4 B) Ar C) LiBr D) Mg E) Nal

Do all liquids freeze at the same rate

How does the conservation of matter relate to balancing equations?

Ethanoic acid and 1-butanol can react to produce water and a compound classified as an 1) aldehyde 2) amine 3) ester 4) halide

Sodium metal reacts with water to form aqueous sodium hydroxide and hydrogen gas. which equation below best describes the balanced equation for this reaction?

2H2 + O2 - - > 2H2O If 16 mol of oxygen were reacted with excess hydrogen gas, how many moles of water would be produced?

Which subatomic particle identifies an atom as that of a particular element? how is this particle related to the atoms atomic number