This assumption is not valid because, there are some elements which exist in two or more forms; they have the same atomic number but differ in their mass number, which meas that they possess different number of neutrons. These type of element are called isotopes. Isotope have the same atomic number and similar physical and chemical properties but they have different number of neutrons and therefore possess different masses.
Answer:
<u>Reasons water is important </u>
Imagine earth without water. The soil, with no water in it and nothing growing on it, would be lifeless, dead, collapsed into dust, sand, clay or rock.
-Water consumption helps lubricate and cushion your joints, spinal cord, and tissues. This will help you enjoy physical activity and lessen discomfort caused by conditions like arthritis.
-Water is a main component of saliva. Saliva also includes small amounts of electrolytes, mucus, and enzymes. It’s essential for breaking down solid food and keeping your mouth healthy.
the answer is true the first one
The mole fraction of HNO3 is 0.225
<u>Explanation:</u>
<u>1.</u>Given data
Density = 1.429 /ml
Mass% = 63.01 g HNO3 / 100g of solution
The mass of 63.01 g is in 100 / 1.142 /ml of solution
Or 63.01 g in 55.7 mL
Molarity = 15.39 moles / L
Mass of water in 100g = 100 - 63.01=36.99 g
So 63.01 grams in 36.99 grams of water
So mass of HNO3 in 1000grams of water = 63.01* x 1000 / 36.99 = 1703
Moles of HNO3 in 1000g = 1703 / 63.01 = 27.03 moles
Molality = 27.03 molal (mole / Kg)
Mole fraction = Mole of HN03 / Moles of water + mole of HNO3
Mole of water = 62/ 18 = 3.44
Moles of HNO3 = 63.01 / 63.01 = 1.000
Mole fraction = 1.000 / 3.44 + 1.000 = 0.225
The mole fraction of HNO3 is 0.225
