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chemistry 2c unit test

Terms in this set (19)

diatomic element
are pure elements that form molecules consisting of two atoms bonded together.
monatomic element
are elements that are stable as single atoms
what gases are diatomic?
hydrogen (H2), nitrogen (N2), oxygen (O2), fluorine (F2), and chlorine (Cl2).
which elements are monatomic?
helium (He)
neon (Ne)
argon (Ar)
krypton (Kr)
xenon (Xe)
radon (Rn)
oganesson (Og)
how much heat in Joules is needed to raise the temperature of 95g ice by 10℃. The specific heat capacity of ice is 2.04J/g(℃)
q=mCΔt
q=(95g)(2.04 J/g C)(10C)
q=1938J
what is the specific heat capacity of a substance for which 100g takes 2000J of energy to increase 25℃?
q=mCΔt
2000J=(100g)(C)(25C)
C=.85J/g.c)
the specific heat capacities of H2, He, and Li, are 14.264J/g(℃), 5.3J/g(℃), and 3.56J/g(℃), respectively. place these elements in order from fastest to slowest to increase in temperature (assume equal mass and heat applied)
Li, He, H2
Q = mcΔT; what does each symbol mean?
Q is the symbol for heat transfer, m is the mass of the substance, and ΔT is the change in temperature. the symbol c stands for specific heat and depends on the material and phase.
what is collision theory?
collision theory states that when suitable particles of the reactant hit each other, only a certain amount of collisions result in a perceptible or notable change; these successful changes are called successful collisions
what happens to the activation energy when a catalyst is added? what happens to the catalyst in the reaction?
catalysts provide a new reaction pathway in which a lower A.E. is offered. a catalyst increases the rate of a reaction by lowering the activation energy so that more reactant molecules collide with enough energy to surmount the smaller energy barrier.
why is activation energy needed in a chemical reaction?
activation energy is needed so reactants can move together, overcome forces of repulsion, and start breaking bonds.
draw an energy diagram. label the reactants, products, and activation energy.
difference between heterogeneous and homogeneous
CH4 + O2 → CO2 + H2O
How many Liters of water are produced by the combustion of 2L of CH4? (assume constant temp and pressure)
2L CH4 | 2lH20/ 1lCH4 | 4 L H20
CH4 + O2 → CO2 + H2O
How many moles of O2 are needed to produce 100g of CO2?
100g CO2 | 1mol CO2/44g | 2mol O2/1mol CO2 | 4.5mol O2
the production of ammonia (NH3) takes place through the reaction of N2(g) and H2(g).
Haber Process
the production of ammonia (NH3) takes place through the reaction of N2(g) and H2(g); Write a balanced equation for the reaction. What is the ratio?
N2+3H2 -> 2NH3; 1:3:2
N2+3H2 -> 2NH3; How many moles of NH3 would form if 2 moles of N2 gas reacted?
2 mol N2 | 2 mol NH3/1mol N2 | 4 mol NH3
N2+3H2 -> 2NH3; How many grams of H2 would be needed to react with 2 moles of N2?
2 mol N2 | 3mol H2/1 mol N2 | 2.016g/1mol H2 | 12.1g H2
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