Chemical reactions

How many elements are in C₆H₁₂O₆?

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-1

Which of the following is a compound?

• Co
• O₂
• C
• CO₂

Tags

NGSS.MS-PS1-1

Which of the following is NOT an element?

• H₂O
• H₂
• O₂
• Au

A scientist spilled a few drops of dilute hydrochloric acid (HCl) on a lab table. For safety purposes, the scientist sprinkled some baking soda (NaHCO3) onto the spill. Which observation would provide the best evidence that a chemical reaction occurred?

• The baking soda and hydrochloric acid combined, and bubbles formed
• The baking soda absorbed the hydrochloric acid.
• Some of the baking soda dissolved in the hydrochloric acid
• The hydrochloric acid evaporated, leaving only the baking soda.

Which of these formulas contain equal numbers of nitrogen atoms?

• Formulas I and III
• Formulas I and IV
• Formulas II and III
• Formulas I, II, and V

The large number written in front of a chemical formula.  It shows the number of molecules.

• Molecule
• Compound
• Coeffiecient
• Subscript

The one or two letters used to represent elements 

• Yield sign
• Coefficient
• Symbol
• Subscript

A physical change is?

• It changes the object into something different
• Objects or substances undergo a change that does not change their chemical composition
• it is just like a chemical reaction
• Paper burning

A chemical change is?

• a shoe lace cut in half
• doesn't change anything
• changes the look of an object
• change that results in the formation of new chemical substances

The small number that is written below the symbol and shows how many atoms of each element is present.  

• Compound
• Molecule
• Coefficient
• Subscript