To what element does Thorium-230 (atomic number-90) decay when it emits an alpha particle (42He) ?

a. 22688Ra

c. 22886Rn

b. 23090Ra

d. 22286Rn

A buffer solution is made using a weak acid, HA. If the pH of the buffer is 9 and the ratio of A - to HA is 100, what is the pKa of HA?

What structure is the fetus being developed

A chemist heats a sample of hydrated lithium nitrate which weighs 170 grams and finds, after heating that it weighs 95.3 grams. What is the percent of water in the hydrate?

A mercury discharge tube produces numerous strong spectral bands. The spectrum of the mercury-filled fluorescent lights in the lab shows three strong bands (one red, one green, and one blue). Why?

Why do atoms form bonds by donating, accepting or sharing electrons with other atoms?

Which question can be answered using the scientific method? A) Which dog food is best for healthy teeth? B) What color is the most attractive? C) What is my purpose in life? D) Which flower smells the best?

For the galvanic cell reaction, expressed below using shorthand notation, what half-reaction occurs at the cathode?

Explain how do you would count the sig figs in the following number, 0.00340670, and what is the answer?

Choose the best answer to each question. Which has the most kinetic energy? a bowling ball with a velocity of 1.5 m/s Or a golf ball with a velocity of 0.5 m/s

Acid indigestion is sometimes neutralized with an antacid such as magnesium hydroxide (Mg (OH) 2). What products will be released when the antacid is mixed with the hydrochloric acid in the stomach