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What coefficient is needed in front of the O₂ molecule to balance the following equation?
2 C₄H₁₀(g) + ___O₂(g)→8CO₂(g)+10H₂O(1)
The reactants shown schematically below represent iron oxide, Fe₂O₃and carbon monoxide, CO. Which of the following is the correct full balanced chemical equation for what is depicted?
Fe₂O₃+ 3 CO → 2 Fe + 3CO₂
If you heat 50 grams of wood and produce 10g of ash, what is the total mass of the products?
more than 50 g
Which has more atoms: a 1-gram sample of cabon - 12 or a 1-gram sample of carbon-13?
a 1-gram sample of carbon-12
If the relative mass of a pingpong ball is 1/20 that of a golf ball, how many pingpong balls would you need to equal the mass of two golf balls?
If the relative mass of a hydrogen atom is 1/4 that of a helium atom, how many helium atoms would you need to equal the mass of 200 hydrogen atoms?
According to the following balanced chemical equation, if you want to generate two moles of H₂O, how many molecules of O₂do you need?
6.022 x 10²³
What is the number of moles of H₂O produced if you combus 0.5 mole of CH₄according to the following balanced equation?
CH₄+ 2 O₂→ CO₂+ 2H₂O
What is the number of molecules of O₂consumed if you combust one mole of CH₄according to the following balanced equation
CH₄ + 2 O₂→ CO₂+ 2 H₂O
1.204 x 0²⁴molecules
Which has more atoms: 64.058 g of sulfur dioxide, SO₂(64.058 amu), or 72.922 g of hydrogen chloride, HCI (36.461 amu)
72.922 g of HCI has more atoms than 64.058 g of SO₂
Small sample of oxygen gas needed in the laboratory can be generated by any number of simple chemical reactions, such as
2 KCIO₃ (s) → 2 KCI (s) + 3 O₂(g)
What mass of oxygen (in grams) is produced when 122.55 g of KCIO₃(formula mass = 122.55 amu) take part in this reaction?
How many moles of water, H₂O, are produced from the reaction of 16 grams methane, CH₄, with an unlimited supply of oxygen, O₂How many grams of H₂O is this?
2.0 moles of water, which is 32 grams
Steel wool wetted with vinegar is sealed within a balloon inflated with air. After several hours, what happens to the volume of the balloon?
The balloon deflates
Why might increasing the temperature alter the rate of a chemical reaction?
The moleculs will have a higher kinetic energy and bump into one another harder.
Two candles of the same mass , one wide and short and the other thin and tall, are placed in identical jars as shown below and lit at the same time. Lids are then placed on each jar. Which candle goes out first?
the short candle
What can you deduce about the activation energy of a reaction that takes billions of years to go to completion? How about a reaction that takes only fractions of a second?
The slow reaction must have a high activation energy while the fast reaction must have a low activation energy
Some reactions are more sluggish then others. To speed up these reactions and save energy
a(n) _________ is sometimes added.
Carefully examine the following reaction sequence for the catalytic formation of ozone, O₃from molecular oxygen, O₂Which chemical is behaving as the catalyst?
Which of the following statements accurately describes the action of ozone?
It absorbs UV radiation and undergoes fragmentation
The portion of the atmosphere that filters out 95 percent of the incident UV radiation is the _____.
Given that the above energy profiles have the same scale, which of the reactions is the most exothermic?
How many moles of H₂bonds are broken if you react nitrogen with hydrogen according to the following reaction?
Use the bond energies below to determine whether the following reaction is exothermic or eanothermic:
H₂+ CI₂→ 2 HCI
H-H (bond energy: 436 kj/mol)
CI-CI (bond energy: 243 kj/mol)
H-CI (bond energy: 431 kj/mol)
Exothermic with more than 50 kj of energy released.
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