8.1 and 8.2 Atoms and Reactions

PS1-1: The model shown represents one molecule of hydrazine, a chemical in rocket fuel. The black spheres represent nitrogen atoms, and the white spheres represent hydrogen atoms. Based on the model, what is the atomic composition of hydrazine?

• 1 atom of nitrogen and 1 atom of hydrogen

• 4 atoms of nitrogen and 2 atoms of hydrogen

• 2 atoms of nitrogen and 2 atoms of hydrogen

• 2 atoms of nitrogen and 4 atoms of hydrogen

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MS-PS1-1

PS1-2: A solid, yellow substance formed when Mr. Simon poured two colorless liquids together at room temperature. Which statement best explains why this demonstrates a chemical reaction?

• The color of the liquids changed to yellow.

• One of the liquids dissolved in the other liquid.

• One of the liquids changed from a liquid to a solid.

• The yellow substance is a solid at room temperature.

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MS-PS1-2

PS1-5: A chemical reaction between two molecules of hydrogen gas (H2) and one molecule of oxygen gas (O2) forms two molecules of water (H2O). Caitlin makes a model to represent this reaction. In her model, gray circles represent hydrogen atoms and white circles represent oxygen atoms, as shown. Caitlin’s model has an error. What can Caitlin do to correct her model?

• Erase a hydrogen atom from the reactant molecule that has two hydrogen atoms.

• Add another hydrogen atom to the product molecule that has one hydrogen atom.

• Change the reactants to three molecules of one hydrogen atom and one oxygen atom.

• Change the product to one molecule of four hydrogen atoms and two oxygen atoms.

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MS-PS1-5

PS1-6: A kerosene lantern is a lighting device. It uses kerosene as fuel. The kerosene is in the base of the lantern, and a wick soaks up the kerosene. Air can flow into the lantern through holes in the lantern.

The diagram shows a kerosene lantern. When the wick is lit, the kerosene in the wick goes through a chemical reaction with oxygen in the air to release energy in the form of light.

How could you increase the amount of time the lantern gives light?

• Increase the size of the base to hold more kerosene.

• Change the shape of the flame to give off more light.

• Increase the size of the air holes to allow more air flow.

• Change the material of the wick to soak up more kerosene.

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MS-PS1-6

PS 1-1: The table shows models of four molecules and lists the atoms of each molecule.

Based on the information in the table, What are the atoms that make up methane, and how many of each atom are there?

How do you know? (Hint: Talk about the other molecules in the table. "I know this because Oxygen gas has...")

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MS-PS1-1

PS1-5: Substance X and Substance Y chemically react as shown in the model.

The products of this reaction are four molecules of the same compound.

a. How does the mass of the products compare to the mass of the reactants? Explain your reasoning.

b. Describe the number of atoms of X and the number of atoms of Y that make up ONE molecule of the product. Explain your reasoning.

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MS-PS1-5

PS1-6: People use hot air balloons to rise high above the ground and be pushed by air currents from one place to

another. The diagram shows a hot air balloon. A type of chemical reaction, called combustion, takes place between propane and oxygen in the burners.

a. Describe what the chemical reaction produces that causes a hot air balloon to rise.

b. Describe something about what would prevent the hot air balloon from traveling far. Explain your reasoning.

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MS-PS1-6

Which two properties would be best to identify an unknown compound?

• conductivity and size

  هدایت او اندازه

  الموصلية والحجم

  পরিবাহিতা এবং আকার

• length and height

  اوږدوالی او لوړوالی

  الطول والارتفاع

  দৈর্ঘ্য এবং উচ্চতা

• solubility and density

  Solubility او کثافت

  الذوبان والكثافة

  দ্রবণীয়তা এবং ঘনত্ব

• mass and temperature

  اندازه او د حرارت درجه

  الكتلة ودرجة الحرارة

  ভর এবং তাপমাত্রা

Which process involves putting objects into different groups based on common properties?

• sequencing

  تسلسل

  التسلسل

  সিকোয়েন্সিং

• inferring

  انفجرا

  استنتاج

• measuring

  اندازه ګیری

  قياس

  পরিমাপ

• classifying

  طبقه بندی

  تصنيف

  শ্রেণিবদ্ধকরণ

The diagram below represents equipment used to separate solids from a liquid. What is the name of this separation process?

• dissolving

  منحل

  حل

  দ্রবীভূত করা

• conducting

  هل

  اجراء

  পরিচালনা

• melting

  ویلون

  صهر

  গলে যাওয়া

• filtering

  چاڼ

  تصفيه

  ফিল্টারিং