How many oxygen atoms are there in 3 molecules of CH3FO?

The arsenic in a 1.223 g sample of a pesticide was converted to H3AsO4 by suitable treatment. The acid was then neutralized, and

Vladimir79 [104]

Answer:

5.471% As₂O₃ in the sample.

Explanation:

...the reaction is: Ag+ + SCN- => AgSCN(s) Calculate the percent As2O3 in the sample. (F.W. As2O3 = 197.84 g/mol).

First, with the amount of KSCN we can find the moles of Ag in the filtrates. As we know the amount of Ag added we can know the precipitate of Ag and the moles of AsO₄ = 1/2 moles of As₂O₃ in the sample:

Moles KSCN = Moles Ag⁺ in the filtrate:

0.01127L * (0.100mol / L)= 0.001127moles Ag⁺

Total moles Ag⁺:

0.0400L * (0.0781mol/L) = 0.0031564 moles Ag⁺

Moles of Ag⁺ in the precipitate:

0.0031564 - 0.001127 = 0.0020294 moles Ag⁺

Moles AsO₄ = Moles As:

0.0020294 moles Ag⁺ * (1mol As / 3 moles Ag⁺) = 6.765x10⁻⁴ moles AsO₄

Moles As₂O₃:

6.765x10⁻⁴ moles AsO₄ * (1 mol As₂O₃ / 2 mol AsO₄) =

3.382x10⁻⁴ moles As₂O₃

Mass As₂O₃:

3.382x10⁻⁴ moles As₂O₃ * (197.84g/mol) = 0.0669g As₂O₃

Percent is:

0.0669g As₂O₃ / 1.223g sample * 100 =

<h3>5.471% As₂O₃ in the sample</h3>

7 0

3 years ago

How many moles of water are in 1.23x10¹8 water molecules? [ ? ]×10[?]

Sergio [31]

Answer:

2.04 x 10⁻⁶ moles H₂O

Explanation:

To find the moles H₂O, you need to multiply the given value by Avogadro's Number. This number is a ratio between molecules and moles, thus granting you the way to convert between both units. It is important to arrange the ratio in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the sig figs of the given value (1.23 x 10¹⁸ molecules).

Avogadro's Number:

6.022 x 10²³ molecules = 1 mole

1.23 x 10¹⁸ molecules H₂O 1 mole
--------------------------------------- x ------------------------------------- =
6.022 x 10²³ molecules

= 2.04 x 10⁻⁶ moles H₂O

5 0

2 years ago

How many moles are present in 10.5 x 10^23 atoms of helium?

Usimov [2.4K]

$10.5 \times {10}^{23}$
multiply by (6.02 times 10^23 atoms)/(1mole, cancel out atoms)

4 0

3 years ago

Which of the following statements does not describe what he structure of an atom an atom has a small dense center called nucleus

nikklg [1K]

Answer:

inside the nucleus of an atom are protons and electrons.

5 0

3 years ago

For the reaction H2(g) + I2(g) 2HI(g), Kc = 50.2 at 445ºC. If [H2] = [I2] = [HI] = 1.75  10-3 M at 445ºC, which one of these st

Soloha48 [4]

Answer: C) The concentration of HI will increase as the system approaches equilibrium.

Explanation:

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as $K_c$

K is the constant of a certain reaction when it is in equilibrium, while Q is the quotient of activities of products and reactants at any stage other than equilibrium of a reaction.

For the given chemical reaction:

$H_2(g)+I_2(g)\rightarrow 2HI(g)$