1st Semester Exam prep

Which statement BEST describes the motion of water molecules as the water changes state from steam to liquid?

• The molecules move faster and occupy more space.

• The molecules move slower and occupy more space.

• The molecules move faster and occupy less space.

• The molecules move slower and occupy less space.

Tags

NGSS.MS-PS1-4

When a mixture of oxygen and hydrogen is ignited in a test tube, the reaction shown occurs.

Hydrogen + Oxygen → Water + Energy

• The total mass increases.

• The total mass decreases.

• The total mass remains the same.

• Part of the mass is changed to heat energy.

  
  

Tags

NGSS.MS-PS1-5

Elements on the right side of the periodic table differ from the elements on the left side in that the elements on the right side?

• tend to form ions by gaining electrons.

• are good electrical conductors.

• generally have very high densities.

• are solid at room temperature.

  
  

The difference between the atomic number of an element and the element’s atomic mass is the number of

• ions

• protons

• neutrons

• electrons

The difference between the atomic number of an element and the element’s atomic mass is the number of

• ions

• protons

• neutrons

• electrons

The difference between the atomic number of an element and the element’s atomic mass is the number of

• ions

• protons

• neutrons

• electrons

The difference between the atomic number of an element and the element’s atomic mass is the number of

• ions

• protons

• neutrons

• electrons

A student concludes that a chemical reaction performed in a classroom investigation was exothermic. To communicate the validity of this conclusion, which would make the BEST visual evidence in a presentation?

• photographs of reactants and products

• listing of masses of reactants and products

• listing of time from start to finish of reaction

• listing of temperatures of reactants and products

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-5

Which is an indication that a chemical change is taking place?

• Iron changes color when heated.

• Gas bubbles form in boiling water.

• Solid wax forms when melted wax falls in ice water.

• A gas forms when vinegar and baking soda are mixed.

Tags

NGSS.MS-PS1-2

How does the concept of conservation of mass apply to chemical reactions?

• The reactants and products have exactly the same atoms.
  

• The reactants and products have exactly the same molecules.
  

• The change in the amount of matter is equal to the change in energy.
  

• The change in the amount of matter is only a small percentage of the total mass.
  

Tags

NGSS.MS-PS1-5