Which of the following are true about atoms? Choose 2 correct answers.

Using the following equations C + O₂ --> CO₂ Which term best describes the left-hand side of this equation?

The following equation shows some carbon and oxygen atoms. Use the graphic to answer the question. C + O₂ --> CO₂ Which is another way to show this chemical equation?

The chemical formula for ammonium is NH₄. N is the symbol for nitrogen and H is the symbol for hydrogen. Which of the following are true about ammonium?

The following graphic shows some carbon and oxygen atoms. Use the graphic to answer the question. C + O₂ --> CO₂ In this equation, which represents the product(s)

Chemical bonds are formed between which parts of atoms?

When two elements chemically combine, they form a—

This equation shows what happens when hydrogen and oxygen are chemically combined. 2H₂ + O₂ → 2H₂O How many total hydrogen atoms are in the product of this equation?

Use the equation to answer the question. CH₄ + 4 Cl₂ → CCl₄ + 4 HCl How many different elements are in this equation?

Read the following information and use it to answer the question. Silicon is a very common element on Earth. It makes up about 28% of the Earth’s crust and is symbolized as Si. You can find silicon in rocks, sand, clay, and soil, but it is usually mixed with other elements like oxygen. The mixtures are called silica and silicates. Scientists can get pure silicon, which is hard and shiny. Pure silicon is used to make computer chips and electronics. Sand and clay (which have silica) are used to make concrete and bricks. Silicates (a compound made of silicon and oxygen) help make glass and pottery. Silicones, made from silicon and other elements, are used in things like waterproofing and lubricants. Based upon this information, which type of silicon would a computer engineer most likely use in their daily work?

A student wants to test how different amounts of heat affect the time it takes for a chemical reaction to occur with two different elements. The student hypothesizes that increasing the heat will make the reaction happen faster. In this experiment, what is the independent variable?

A science class is testing how different amounts of vinegar affect the speed of a baking soda reaction. They use three different amounts of vinegar: 50 milliliters, 100 milliliters, and 150 milliliters. They then mix each amount of vinegar with a fixed amount of baking soda and measure how quickly the bubbles form. What is the dependent variable in this experiment?

Choose the correct answer in the drop-down to complete the sentence. The law of conservation of matter states that matter cannot be created or destroyed, though the properties of matter can change. These two types of changes are called ____.

Compounds can be represented by chemical formulas. Each element in the compound is represented by its unique symbol. The number of atoms of each element in the compound (when more than one) is shown as a small number to the right of the element symbol. What is the correct name for this small number?

Which tool would be most appropriate for measuring the mass of a small rock, and what would be the most appropriate units? (choose 2 answers)

Chlorine, sulfur, and oxygen all have atoms; however, the atoms of one element differ from those of the other element because of the number of which of the following subatomic particles?

Which of the following statements correctly describes how elements are represented in science?

Why is it important to collect data accurately during a science experiment?

Identify the number of atoms that are in the following chemical formula. $$Fe_2O_3$$