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WITCHER [35]
3 years ago
8

In 1803, the British chemist John Dalton proposed several atomic theories. Which one of his theories was later shown to be incor

rect?
I. Atoms are indivisible and indestructible particles.

II. All atoms of the same element are exactly alike.

III. Atoms of different elements are different.

IV. Atoms combine in specific numerical ratios to form compounds.

A. II only
B. II & III only
C. I & II only
Chemistry
1 answer:
Serggg [28]3 years ago
6 0
Option C: I and II only.

The atoms have subparticles and the isotops are atoms of the same element that differ in the number of neutrons.
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What is the molar mass of a substance?
Masja [62]
<span>Molar mass is the mass of a given substance divided by the amount of that substance, measured in g/mol. So probably A.)</span>
6 0
3 years ago
Read 2 more answers
Calculate the concentration 3.8g of copper sulfate, CuSO4 dissolved in 250cm4 of water
11Alexandr11 [23.1K]

Answer:

Molarity = 0.08 M

Explanation:

Given data:

Mass of copper sulfate = 3.8 g

Volume of water = 250 cm³  (250/1000 = 0.25 L)

Concentration of solution = ?

Solution:

Number of moles of copper sulfate:

Number of moles = mass/molar mass

Number of moles = 3.8 g/ 159.6 g/mol

Number of moles = 0.02 mol

Concentration:

Molarity = Number of moles / volume in L

By putting values,

Molarity = 0.02 mol / 0.25 L

Molarity = 0.08 mol/L

Molarity = 0.08 M

6 0
3 years ago
In order to prepare a 0.523 m aqueous solution of potassium iodide, how many grams of potassium iodide must be added to 2.00kg o
Lerok [7]
M = amount of the solute  / mass of the <span>solvent

0.523 = x / 2.00 

x = 0.523 * 2.00

x = 1,046  moles

molar mass KI = </span><span>166.0028 g/mol
</span><span>
Mass = 1,046 * 166.0028

Mass </span>≈<span> 173.63 g

hope this helps!

</span>
6 0
4 years ago
A 260.0 −mL buffer solution initially contains 2.5×10−2 M of HCHO2 and 2.5×10−2 M of NaCHO2
FinnZ [79.3K]

The mass of HCHO2 and NaCHO2 to be added to the buffer solution are 0.23g and 0.44g respectively

Data;

  • Volume of solution = 260mL
  • conc. of HCHO2 = 2.5*10^-2M
  • conc. of NaCHO2 = 2.5*10^-2M

<h3>Mass of Reagent Added</h3>

To calculate the mass of reagent added,  let's start with HCHO2

The mass of HCHO2 to be added is the number of moles of HCHO2 multiplied by it's molar mass.

260*10^-^3 * 2.5*10^-^2 * 46 = 0.229 = 0.23g

The mass of NaCHO2 to be added in the buffer solution is

260*10^-^3*2.5*10^-^2*68 = 0.442 = 0.44g

The mass of HCHO2 and NaCHO2 to be added to the buffer solution are 0.23g and 0.44g respectively

Learn more about buffer solution here;

brainly.com/question/22390063

3 0
2 years ago
For a particular reaction, Δ H ∘ = 55.4 kJ ΔH∘=55.4 kJ and Δ S ∘ = 94.1 J/K. ΔS∘=94.1 J/K. Assuming these values change very lit
nadezda [96]

Answer:

The temperature at which the reaction changes from non-spontaneous to spontaneous is 588.735 K

Explanation:

The spontaneity of a reaction is determined by the change in Gibbs Free Energy, \Delta G^{0}.

\Delta G^{0} =\Delta H^{0} -T\Delta S^{0}

If \Delta G^{0} is greater than zero, then a reaction is feasible.

If \Delta G^{0} is less than zero, then a reaction is not feasible.

To determine the temperature at which the reaction changes from non-spontaneous to spontaneous, we should equate the \Delta G^{0} to zero.

We take \Delta G^{0}=0 as the limiting condition.

T=\frac{\Delta H^{0}}{\Delta S^{0}}=\frac{55.4\times10^{3}}{94.1}=588.735K

Therefore, the temperature is: 588.735K

7 0
4 years ago
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