Chemical Reactions

Complete the sentence.

During a chemical reaction, atoms ________.

Completa la oración. Durante una reacción química, los átomos ________.

• can appear

• can disappear

• get rearranged

• stop moving and vibrating

Tags

NGSS.MS-PS1-5

What always happens in a chemical reaction?

¿Qué sucede siempre en una reacción química?

• Some atoms of existing substances disappear.

• Some substances change phase.

• New atoms appear and form new substances.

• New substances form from atoms of existing substances.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Identify the product(s) in the following chemical reaction:

Chromium oxide + Carbon → Chromium + Carbon monoxide

• Chromium and carbon.

• Chromium and carbon monoxide.

• Chromium and carbon dioxide.

• Chromium oxide and carbon.

Tags

NGSS.MS-PS1-2

In chemical reactions, a product is _________.

En reacciones químicas, un producto es _________.

• any substance that is made of the greatest number of atoms

• any substance that is made from the least number of atoms

• any substance that is to the left of the arrow

• any substance to the right of the arrow

What is the role of the arrow sign in a chemical reaction?

¿Cuál es el papel del signo de flecha en una reacción química?

• Making sure atom counts on each side are the same.

• Separating products and reactants.

• Showing which substances were in the container first and which substances were added later.

• Showing which substances are solids and which are liquids or gases.

In a chemical reaction, the mass of the reactants is 200 grams. Which of the following could represent the mass of the products?

• 26.6 grams.

• 200 grams

• 3.3 grams.

• 2000 grams.

Tags

NGSS.MS-PS1-5

Which of the following describes the law of conservation of mass?

¿Cuál de los siguientes describe la ley de conservación de la masa?

• The mass of the reactants is greater than the mass of the products.

• The mass of the products equals the mass of the reactants.

• The mass of the products is greater than the mass of the reactants.

• The products will have the same states of matter as the reactants.

Tags

NGSS.MS-PS1-5

Complete the sentence.

During a chemical reaction, __________.

• a small amount of matter is destroyed during the process

• the mass of the atoms of the product(s) is greater than that of the reactant(s)

• a new substance(s) with the same number of atoms as the initial substance(s) is formed

• the number of atoms in the product(s) is less than that of the reactant(s)

Tags

NGSS.MS-PS1-5

A substance that is formed as the result of a chemical reaction is a __________________

• Product

• Reactant

• Starters

• Enders

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is an example of a chemical change?

• water freezes to form ice

• sugar dissolves in water

• gasoline burns in a car engine

• a piece of metal expands when it is heated

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5