The balanced chemical equation below shows the decomposition of water into hydrogen and oxygen gas. 2H2O(l) → O2(g) + 2H2(g) How many atoms are in the products?

Ms. Trischitta measured the mass of a closed and sealed beaker containing several ice cubes. The mass was 100g. An hour later the ice cubes had melted, and Ms. Trischitta measured the mass of the beaker again. What was the mass of the beaker?

In the chemical reaction shown, all the HCl and Zn will react to form H2 and ZnCl2. Which of the following describes the results of this reaction?

Consider the reaction of sodium and water below and select all the correct statements about it. 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

The order of elements in the periodic table is based on

As you move from left to right across the periodic table, elements

Most elements are

A mixture of two gases is in a rigid container at 25°C. The particle diagram shows a mixture of neon gas and argon gas. The temperature was decreased below the boiling point of each gas. Which diagram shows what would happen to the gas mixture?

Which diagram correctly represents the mass of one of the chemical reactions?

A student was reading about the gases in air. Ozone helps protect Earth from harmful ultraviolet rays that come from the sun. Certain types of pollution created by humans have caused a hole in the ozone layer. This hole is over the South Pole and could become larger if this type of pollution increases. Which question should the student ask to determine if ozone is an elemental molecule? (7.PS1.2)

A student has been learning about atoms. He wrote a small paragraph describing one. The student describes particles on the edge of the atom. Which statement supports the student’s claim that the particles on the edge of the atom do not move away from the center? (7.PS1.1)

Using the data table and a periodic table, which three of these compounds are most likely to be conductors of electricity? (7.PS1.5)

Which three statements about the gas in the containers are true? (7.PS1.6)

Students were looking at coins during lunch. One of them noticed that older pennies looked and felt different from new pennies. The students decided to investigate whether all pennies are made of the same materials. The students measured the mass and the volume of 10 pennies and then divided the mass by the volume to determine the density. The measurements were recorded in a data table. The teacher told the students that newer pennies contain copper and zinc. Copper has a density of 8.96 g/cm³. Zinc has a density of 7.1 g/cm³. Which statement is best supported by the data and information from the teacher?

Which of the following can indicate that a chemical change has occurred?

Which increase in temperature would require the most thermal energy? Assume all the H₂O (water, ice or water vapor) samples are the same size and that temperature changes occur at standard pressure.

Lily is doing a science experiment with a substance in a sealed jar. At first, the substance’s molecules are moving around each other. What will happen to Lily’s substance if she transfers energy into the substance and causes a phase change? After the phase change, the substance’s molecules will move . . .

Here is a portion of the periodic table. Which two elements are most likely to have similar physical properties?

It can be difficult to show what particles are actually doing because we can’t see them. One way to model particles is shown. Study the diagram and choose the correct statement. Which image correctly represents the hot and cold-water particles?