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3 years ago

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Describe how the proton, electron and neutron were experimentally discovered.

1 answer:

alexandr1967 [171]3 years ago

5 0

The discovery of protons can be attributed to Rutherford. ... Given the discoveries of electrons in 1897 by Thomson, Rutherford and other scientists decided that a positively charged particle must exist to center the electron to create equally neutral atoms. Thomson proposed the name 'positive rays'.

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What is the mole fraction of NaCl in a mixture containing 7.21 moles NaCl, 9.37 moles KCL, and 3.42

GrogVix [38]

Answer : The mole fraction of NaCl in a mixture is, 0.360

Explanation : Given,

Moles of $NaCl$ = 7.21 mole

Moles of $KCl$ = 9.37 mole

Moles of $LiCl$ = 3.42 mole

Now we have to calculate the mole fraction of $NaCl$ .

$\text{Mole fraction of }NaCl=\frac{\text{Moles of }NaCl}{\text{Moles of }NaCl+\text{Moles of }KCl+\text{Moles of }LiCl}$

Now put all the given values in this formula, we get:

$\text{Mole fraction of }NaCl=\frac{7.21}{7.21+9.37+3.42}=0.360$

Therefore, the mole fraction of NaCl in a mixture is, 0.360

3 0

3 years ago

Question 14 A student dissolves 1.5g of styrene C8H8 in 225.mL of a solvent with a density of 1.02/gmL . The student notices tha

Yuki888 [10]

We must to know:

Cm = molarity = niu / Vs, when the niu = no. of moles and Vs = Volume of solution

the no. niu = mass / molecular mass of substance

molecular mass of C8H8 = 12x8+8x1 = 104 g/mol

=> niu = 1,5 / 104 = 0,0144 moles C8H8

=> Cm = 0,0144/0,225 = 0,06 mol/L

Cmm = molality = niu (C8H8) / mass of solvent (kg)

=> p = mass / V => mass (solvent) = p x V

=> 225 x 1,02 = 229,5 g solvent = 0,2295 kg solvent

=> Cmm = 0,0144 / 0,229,5 = 0,063

8 0

3 years ago

Read 2 more answers

How are radioactive isotopes used to determine the absolute age of igneous rock?

Likurg_2 [28]

Answer:

d) all of the above

5 0

2 years ago

How much NaOH (in grams) is needed to prepare 463 mL of solution with a pH of 10.020?

tino4ka555 [31]

Answer: $1.94\times 10^{-3}g$ of NaOH

Explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration.

$pH=-\log [H^+]$

Putting in the values:

$10.020=-\log[H^+]$

$[H^+]=9.55\times 10^{-11}$

$[H^+][OH^-]=10^{-14}$

$[OH^-]=\frac{10^{-14}}{9.55\times 10^{-11}}=1.05\times 10^{-4}M$

$NaOH\rightarrow Na^++OH^-$

$Molarity=\frac{moles\times 1000}{\text {Volume in ml}}$

$1.05\times 10^{-4}M=\frac{moles\times 1000}{463ml}$

moles = $4.86\times 10^{-5}$

Mass of $NaOH=moles\times {\text {Molar mass}}=4.86\times 10^{-5}\times 40=1.94\times 10^{-3}g$

Thus $1.94\times 10^{-3}g$ of NaOH is needed to prepare 463 mL of solution with a pH of 10.020

8 0

3 years ago

Given that the specific heat of chromium is 0.455J/g∙K find the final temperature after 35.9J of energy is removed from 11.7g of

ryzh [129]

Answer:

before I tell you the answer what is your name?

Explanation:

6 0

3 years ago