Answer: number of atoms is 5.21 · 10^24
Explanation: Atomic mass of Be is 9.012 g/mol.
Number of moles n = m/M = 78.0 g / 9.012 g/mol =
Multiply this with Avogadro number Na = 6.022*10^23 1/mol
Answer:
Explanation:
"Nature does this job through a process called the water cycle. Also known as hydrologic cycle, the water cycle is a phenomenon where water moves through the three phases (gas, liquid and solid) over the four spheres (atmosphere, lithosphere, hydrosphere and biosphere) and completes a full cycle. The water cycle has many effects: it regulates the temperature of the surroundings. It changes weather and creates rain. It helps in conversion of rocks to soil. It circulates important minerals through the spheres. It also creates the many geographical features present on earth like the ice caps of mountains, icebergs, the rivers and the valleys, lakes, and more. Hence it is quite important to understand and learn the processes of the water cycle."
-Water cycle a guide for students.
They have same chemical properties
for example the elements of group VIII are called noble gases .They are unreactive, odorless and colorless.
As the question tells you, you need to use the formula
% mass= mass of solute/ mass of solution x 100
mass solute= 30.0 g
mass of solution= 30.0 + 270.0= 300.0 g
% mass= 30.0/ 300.0 x 100= 10%
answer is B
