All categories

3 years ago

What is the mass number of the atom shown? a. 11 b. 18 d. 20 C. 19

Chemistry

2 answers:

PolarNik [594]3 years ago

6 0

Answer:

Explanation:it is 11

Anastasy [175]3 years ago

6 0

It is 20 because the mass is proton + neutron!!! hope this helped :)

You might be interested in

A person buildirig an aquarium would benefit from adding a livce rock to their aquarium because ?

spayn [35]

It introduces a diverse array of bacteria, algae, and invertebrates to the closed marine environment and functions as a superior biological filter

7 0

3 years ago

Determine the molality of a solution of methanol dissolved in ethanol for which the mole fraction of methanol is 0.135. Give you

Alja [10]

Answer: The molality of the solution is 0.11 m

Explanation:

We are given:

Mole fraction of methanol = 0.135

This means that 0.135 moles of methanol is present in 1 mole of a solution

Moles of ethanol = 1 - 0.135 = 0.865 moles

To calculate the mass for given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of ethanol = 0.865 moles

Molar mass of ethanol = 46 g/mol

$0.865mol=\frac{\text{Mass of ethanol}}{46g/mol}\\\\\text{Mass of ethanol}=(0.865mol\times 46g/mol}=39.79g$

To calculate the molality of solution, we use the equation:

$Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ (in grams)}}$

Where,

$m_{solute}$ = Given mass of solute (methanol) = 0.135 g

$M_{solute}$ = Molar mass of solute (methanol) = 32 g/mol

$W_{solvent}$ = Mass of solvent (ethanol) = 39.79 g

Putting values in above equation, we get:

$\text{Molality of methanol}=\frac{0.135\times 1000}{32\times 39.79}\\\\\text{Molality of methanol}=0.106m\approx 0.11m$

Hence, the molality of the solution is 0.11 m

6 0

4 years ago

A gas occupies a volume of 85.0 liters at a pressure of 2.24 atm and a temperature of 22.5 degrees celsius. How many moles of ga

White raven [17]

Answer:

n = 7.86 mol

Explanation:

This question can be solved using the ideal gas law of PV = nRT.

Temperature must be in K, so we will convert 22.5C to 295 K ( Kelvin = C + 273).

R is the ideal gas constant of 0.0821.

(2.24atm)(85.0L) = n(0.0821)(295K)

Isolate n to get:

n = (2.24atm)(85.0L)/(0.0821)(295K)

n = 7.86 mol

8 0

3 years ago

A compound is found to contain 73.23% xenon name 26.77% oxygen by mass. What is the empirical formula for this compound ?

Luba_88 [7]

The empirical formula is XeO₃.

Explanation:

Assume 100 g of the compound is present. This changes the percents to grams:

Given mass in g:

Xenon = 73.23 g

Oxygen = 26.77 g

We have to convert it to moles.

Xe = 73.23/ 131.293 = 0.56 moles

O = 26.77/ 16 = 1.67 moles

Divide by the lowest value, seeking the smallest whole-number ratio:

Xe = 0.56/ 0.56 = 1

O = 1.67/ 0.56 = 2.9 ≈3

So the empirical formula is XeO₃.

6 0

3 years ago

Write the electron configuration for sodium

professor190 [17]

Answer:

1s^2 2s^2 2p^6 3s^1

Explanation:

8 0

3 years ago