What is the half-life of sodium-25 if 1.00 gram of a 16.00-gram sample of sodium-25 remains unchanged after 237 seconds?

(1) 47.4 s (3) 79.0 s

(2) 59.3 s (4) 118 s

Why is there a dip in ionization energies between the elements Be and B, between Mg and Al, and between Ca and Ga?

What level of Organization is shown in the human heart

A scuba tank has a pressure of 195 atm at a temperature of 10 degree Celsius. The volume of the tank is 350 L. How many moles of air are in the tank?

This stadium can hold 100,000, or 1 x 10^5, people. The number of atoms in a grain of iron is about 1 x 10^18.

Particles in a plasma experience collisions than particles in a solid. Based on their state of matter alone, is it easier to speak of the shape of the Sun or the Moon? Two unknown substances are in identical beakers.

A catalyst increases the rate of a chemical reaction by

What energy is changed to cell energy in stage 1 of photosynthesis. true or false

A person produces two sound waves with a flute, one immediately after the other. Both sound waves have the same pitch, but the second one is louder. Which of the following properties is greater for the second sound wave?

A voltaic cell is constructed with two silver-silver chloride electrodes, each of which is based on the following half-reaction: AgCl (s) + e-→Ag (s) + Cl - (aq). The two cell compartments have [Cl-] = 1.51*10-2 M and [Cl-] = 2.90 M, respectively.

How many liters of chlorine gas can be produced when 0.98 l of hcl react with excess o2 at stp? 4hcl (g) + o2 (g) - > 2cl2 (g) + 2h2o (g) ?