How many moles are present in 2.95 x1024 molecules of water (H20)

Name the SI base units that are important in chemistry, and give the SI units for expressing the following: (a)length, (b) volum

kirza4 [7]

Answer and Explanation:

The basic unit which are that are important in chemistry are meter, kilogram ,mol, $m^3$

Candela which is the unit of luminous of intensity is not so important in physics

(a) SI unit of length is meter (m)

(b) Si unit of volume is $m^3$

(c) Si unit of mass is kilogram (kg)

(d) SI unit of time is second (s)

(e) SI unit of temperature is kelvin (K)

4 0

3 years ago

The cube has a mass of 72.9 g. What is its density in g/cm3? What substance is it?

sashaice [31]

If the cube is 3 cm on each side, then it has a volume of 27 cm^3 (3 x 3 x 3). Density is mass divided by volume, so its density is 72.9/27 = 2.7 g/cm^3.

Going by the density, the cube is made of Aluminium - density is a fairly unique quantity

6 0

3 years ago

What is the ph of a solution labeled .30 trimethylamine k for trimethylamine is 7.42 x 10^4

valentina_108 [34]

Answer:the pH is 12

Explanation:

First We need to understand the structure of trimethylamine

Due to the grades of the bond in the nitrogen with a hybridization sp3 is 108° approximately, then is generated a dipole magnetic at the upper side of the nitrogen, this dipole magnetic going to attract a hydrogen molecule of the water making the water more alkaline

C3H9N+ H2O --> C3H9NH + OH-

$k=\frac{[C3H9NH]*[OH-]}{[C3H9N]}$

Then:

The concentration of the trimethylamine is 0.3 and the concentration of the ion C3H9NH is equal to the OH- relying on the stoichiometric equation. We could find the concentration of the OH- ion with the square root of the multiplication between k and the concentration of trimethylamine

[OH-]= $\sqrt{ 0.3*7.42x10^{-4}}$