Chemistry Unit Test CASC 22-23

Many common household substances may be classified as acids or bases. According to the pH scale,

• lemons are a strong base, while bleach is a strong acid

• milk is a weak acid, while baking soda is a weak base

• eggs are a weak base, and tomatoes have a neutral pH

• Water and stomach acid have the same pH

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NGSS.MS-PS1-2

Which of the four containers represents a compound?

• Cl

• H₂O

• N₂

• Na

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NGSS.MS-PS1-1

Describe the mass of the reactants and products given the balanced chemical reaction.

• The mass of the products is two thirds that of the reactants.

• the mass of the reactants equals the mass of the products

• the mass of the reactants is less than the mass of the products

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

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

Using the Law of Conservation of Matter, determine the number of grams of iron sulfide (FeS) that will be produced in this reaction:

112g Fe + 64g S --> __g FeS

• 48 grams

• 64 grams

• 112 grams

• 176 grams

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NGSS.MS-PS1-5

According to the scale, which of these substances is the strongest acid?

• NaOh

• blood

• bleach

• lemon juice

During a physical science lab investigating chemical reactions, several students placed a 30g antacid tablet in a zip-lock bag that has a mass of 20g. They recorded the masses of the tablet and the bag. Then they added 50 grams of water and quickly sealed the bag. The tablet began to fizz and soon disappeared. The bag was filled with gas. What can you conclude about the amount of gas produced if the mass of the liquid after the reaction is completed is still 50 grams?

• 30 grams

• 90 grams

• 80 grams

• 50 grams

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

Natural resources are useful materials that we get from the Earth such as coil, oil, water, and natural gas. They occur naturally, which means that humans did not make them. Humans use natural resources to form new substances that can be beneficial to us, such as synthetic materials. Synthetic materials are formed when humans deliberately mix substances together for the express purpose of creating new materials with desirable properties and are a big part of our day to day lives. Most synthetic materials are the result of chemical reactions during which the atomic structures of the original substances are rearranged to form the new material.

Which of these are examples of natural resources? Select ALL that apply.

• nylon

• oil

• cotton

• plastic

• coal

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NGSS.MS-PS1-3

Mrs. Smith is demonstrating a chemical change for her class. She places 15 grams of baking soda into a beaker. Next she adds 15 grams of vinegar to the same beaker. When the two compounds make contact, they bubble and fizz a great deal. She places the beaker on the balance and notes that the mass of the solution in the beaker is less than the expected 30 grams.

Explain why the mass of the solution in the beaker is less than 30 grams.

• The new products have less mass than the original reactants.

• Mass is always lost in a chemical reaction.

• The gas that was released changed the mass.

• The balance was not working correctly.

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

All fabrics can be characterized as either natural or synthetic fibers (or a blend of the two). Natural fibers come from plants and animals, while synthetic fibers are made from chemical compounds, and each is used in the textile industry for different reasons. Evaluate the chart.

Which natural fibers come from a plant source?

• cashmere and cotton

• cotton and flax

• jute and silk

• nylon and polyester

Explain why the model of this chemical reaction obeys the Law of Conservation of Matter.

• because they both start and end with two sets of particles

• because there are the same number of atoms of each element shown on both sides

• because they both start and end with the same types of particles

• because they both start and end with diatomic (two-atomed) molecules

Tags

NGSS.MS-PS1-5