How do we find mass number of elements in chemistry?

A wooden object from the site of an ancient temple has a carbon-14 activity of 10 counts/min compared with a reference piece of wood cut today that has an activity of 40 counts/min.

How many atoms of each type are represented in each of the following 3n2?

The unheated gas in the above system has a volume of 20.0 L at a temperature of 25.0 °C and a pressure of 1.00 atm. The gas is heated to a temperature of 100.0 °C while the volume remains constant. What is the pressure of the heated gas?

At do oxygen (O) and bromine (Br) have in common? They both tend to gain electrons to gain stability. They both have seven valence electrons. They are both halogens. They are both unreactive.

What units are used for pressure, volume, and Temperature in the ideal gas law when R=0.0821? 1. Atm, Liters, and Kelvin 2. Atm, mL, and Celsius 3. mmHg, Liters, and Kelvin 4. kPa, Liters, and Celsius

In the Table of Atomic Particles, various symbols have two numbers. The top number represents the atomic mass of the particle, what do the bottom numbers represent? Select all that apply.

A chemist is working on a reaction represented by this chemical equation: FeCl2 + 2KOH → Fe (OH) 2 + 2KCl. If the chemist uses 4.15 moles of iron (II) chloride and 3.

vWould radiation with a wavelength 0.91 nm or a frequency of 5.9*1011 s-1 be detected by an X-ray detector? Would radiation with a wavelength 0.91 or a frequency of 5.9*1011 be detected by an X-ray detector? Only the radiation with a wavelength 0.

Why Thioacetamide is heated?

Which compound decreases in solubility as the temperature of the solution is increased from 10c to 50c