By studying a star's spectrum, scientists can work out its chemical make-up and temperature. what instrument do astronomers' use to carry out this task?
a) space probe
b) spectroscope
c) radio telescope
d) light telescope

Which statement best describes isomers? a. isomers are alcohols that have the same functional group. b. isomers have at least one carbon-carbon double bond. c. isomers have the same molecular formula but different structural properties.

Which best describes eras and periods?

El amoniaco y el fluor reaccionan para formar tetrafluoruro de dinitrogeno y fluoruro de hidrogeno. segun la reaccion: nh3 + f2 ⇒ n2f4 + hf si reaccionan 5 gramos de amoniaco y 20 gramos de fuor, ¿cuantos gramos de fluoruro de hidrogeno se producen?