Carbon-14 has a half-life of 5720 years and this is a first order reaction. if a piece of wood has converted 75% of the carbon-14, how old is it?
a. 11440 years
b. 2345 years
c. 4750 years
d. 4290 years
e. 1430 years

Consider the two electron arrangements for neutral atoms a and b. are atoms a and b the same element? a - 1s2, 2s2, 2p6, 3s1 b - 1s2, 2s2, 2p6, 5s1

Marcel just purchased 1.69 grams of iron fillings in order to make living putty for his 6 year old niece. how many moles of iron are made in his sample?

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)