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3 years ago

How many neutrons in an atom of 30p? O a. 17 O b. 30.974 O c. 15 O d. 14 O e. 16

Chemistry

1 answer:

jeyben [28]3 years ago

6 0

Answer:

The correct option is: c. 15

Explanation:

Phosphorous is a chemical element which belongs to the group 15 of the periodic table and has atomic number 15. It is a highly reactive non-metal of the p-group.

Since, atomic number of an atom is the number of electrons and number of protons for neutral atoms.

So, the number of protons = number of electrons = 15

The atomic mass is obtained by adding the number of neutrons and the protons.

So, number of neutrons + number of protons = 30

So, number of neutrons + 15 = 30

Therefore, the number of neutrons in ³⁰P = 15

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When 63.4 g of glycine (C2HNO2 are dissolved in 700. g of a certain mystery liquid X, the freezing point of the solution is 7.9

bearhunter [10]

Answer: The van't Hoff factor for iron(III) chloride in X is 3.64

Explanation:

Depression in freezing point is given by:

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

$\Delta T_f=7.9^0C$ = Depression in freezing point

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

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

m= molality

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

$7.9^0C=1\times k_f\times \frac{63.4g\times 1000}{75.07g/mol\times 700g}$

$k_f=6.55^0C/m$

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

$13.3^0C=i\times 6.55\times \frac{63.4g\times 1000}{162.2g/mol\times 700g}$

$i=3.64$

Thus the van't Hoff factor for iron(III) chloride in X is 3.64

3 0

3 years ago

Describe the formation of an image in a pinhole camera

Alla [95]

Answer:

Explanation:

A pinhole camera is a simple camera without a lens but with a tiny aperture, a pinhole camera – effectively a light-proof box with a small hole in one side. Light from a scene passes through the aperture and projects an inverted image on the opposite side of the box, which is known as the camera obscura effect.

8 0

3 years ago

How many total atoms are there in 74.5 g of carbon dioxide (CO2)? I am not sure if I did it correct I ended up getting 1.02 * 10

AlekseyPX

Molar mass CO₂ = 44.0 g/mol

44.0 g ----------------- 6.02x10²³ molecules
74.5 g ----------------- ??

74.5 x ( 6.02x10²³) / 44.0

= 1.019x10²⁴ molecules of CO2

Calculate the number of atoms :

CO₂ => 1 atom of Carbon , 2 atoms of Oxygen ( 1 + 2 = 3 atoms )

therefore:

1 molecule CO2 ---------------------- 3 atoms
1.019x10²⁴ CO2 --------------------- ?? atoms

3 x ( 1.019x10²⁴) / 1 =

= 3.057x10²⁴ atoms of CO₂

hope this helps!

5 0

3 years ago

Which one of the following scenarios accurately describes a condition in which resonance can occur? A. A column of air has a hei

bixtya [17]

The correct answer from the choices is: D

Resonance is an event where an external force or vibration moves another system to oscillate with higher amplitude at certain frequences or there is a transfer of energy between two or more different storage modes.

7 0

3 years ago

HCl + - CaCO3 → CaCl2 + _H20 + __ CO2

balu736 [363]

Answer:

CaCO3 + 2HCl → CaCl2 + H2O + CO2

Calcium Carbonate + Hydrogen Chloride → Calcium Chloride + Water + Carbon Dioxide

Calcium carbonate is not very soluble in water. This is an acid-base reaction (neutralization): CaCO3 is a base, HCl is an acid.

5 0

2 years ago