Shells (electrons) - located in the cloud
nucleus- located in the center
energy level - is determined by the electron count ( level 1 - 2 electrons
level 2 - 8 electrons
level 3- 18 electrons)

5 0

3 years ago

Which term represents a chemical reaction?

Marizza181 [45]

Answer:

vaporization

Explanation:

7 0

3 years ago

A certain substance X has a normal freezing point of -6.4 C and a molal freezing point depression constant Kf= 3.96 degrees C.kg

Brut [27]

Answer: $1.0\times 10^2g$

Explanation:

Depression in freezing point is given by:

$\Delta T_f=i\times K_f\times m$

$\Delta T_f=T_f^0-T_f=(-6.4-(13.6))^0C=7.2^0C$ = Depression in freezing point

i= vant hoff factor = 1 (for non electrolyte like urea)

$K_f$ = freezing point constant = $3.96^0C/m$

m= molality

$\Delta T_f=i\times K_f\times \frac{\text{mass of solute}}{\text{molar mass of solute}}\times \text{weight of solvent in kg}}$

Weight of solvent (X)= 950 g = 0.95 kg

Molar mass of non electrolyte (urea) = 60.06 g/mol

Mass of non electrolyte (urea) added = ?

$7.2=1\times 3.96\times \frac{xg}{60.06 g/mol\times 0.95kg}$

$x=1.0\times 10^2g$

Thus $1.0\times 10^2g$ urea was dissolved.

8 0

4 years ago

Calculate the number of moles found in 3.045x1024 atoms of helium.<br><br> PLS HELP

Kisachek [45]

Explanation:

so for this u have to use this equation where

Moles = number of particle/6.02×10^23

= 3.045 × 10^24/6.02×10^23

= 5.0581

write it to 3 S.F so 5.06 moles

4 0

3 years ago

3 points Given 0.65 moles KNO3: (a) Convert to grams (b) Convert to particles. ​

3 points Given 0.65 moles KNO3: (a) Convert to grams (b) Convert to particles.