Rates of Reaction Review

What would likely happen if you were to touch the flask in which an endothermic reaction were occurring?

• The flask would probably feel cooler than before the reaction started.

• The flask would probably feel warmer than before the reaction started.

• The flask would feel the same as before the reaction started.

• none of the above

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

The "?" in the energy diagram below represents the energy required for reactants to form the activated complex. This is called the ____________________.

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NGSS.HS-PS1-4

Given the equation: 2 Mg (s) + O₂ (g) ---> 2 MgO (s) + 72.3 kJ, which of the following is true?

• The reaction is endothermic

• ΔH = -72.3 kJ

• ΔH = 72.3 kJ

• The reaction absorbs heat

Tags

NGSS.HS-PS1-4

The specific heat of wood is 2.03 J/g°C. How much heat is needed to convert 550g of wood at -15.0°C to 10.0°C? Please input the most accurate numeric answer to one decimal location (for example: 1000.0). No units should be entered.

Tags

NGSS.HS-PS3-4

At what stage of a chemical reaction is chemical energy at its highest level?

• when only reactants are present

• when only products are present

• when an activated complex exists

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NGSS.HS-PS1-4

Which of the following chemical equations best represents the thermochemical equation: 2 Cl₂ (g) + 7 O₂ (g) ---> 2 Cl₂O₇(g) ΔH = +130 kJ

• 2 Cl₂ (g) + 7 O₂ (g) + 130 kJ ---> 2 Cl₂O₇(g)

• 2 Cl₂ (g) + 7 O₂ (g) ---> 2 Cl₂O₇(g) + 130 kJ

• 2 Cl₂ (g) + 7 O₂ (g) ---> 2 Cl₂O₇(g) + 260 kJ

• 2 Cl₂ (g) + 7 O₂ (g) + 500 kJ ---> 2 Cl₂O₇(g)

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

If 200 grams of water is to be heated from 24.0°C to 100°C to make a cup of tea, how much heat must be added? The specific heat of water is 4.18 J/g°C. For your answer: type the exact whole number answer. no decimals or units.

Tags

NGSS.HS-PS3-1

Why does a higher temperature cause a reaction to go faster?

• Collisions between molecules occur more slowly so there is more time to react.

• Collisions are not as frequent but each collision has more energy.

• Collisions occur more frequently and they occur with greater energy.

• Collisions have less energy so molecules are less likely to bounce away from one another.

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NGSS.HS-PS1-5

Why does a catalyst cause a reaction to proceed faster?

• A catalyst increases the frequency of collisions.

• A catalyst increases the total energy of collisions.

• A catalyst decreases the activation energy of reaction.

• A catalyst decreases the need for an activated complex.

Tags

NGSS.HS-PS1-5

In which direction will the reaction below shift if more HCl was added? 4 HCl (g) + O₂ (g) ⇌ 2 Cl₂ (g) + 2 H₂O (g)

• Left

• Right

• Neither direction

Tags

NGSS.HS-PS1-5