Which of these is an indication that a chemical reaction has occurred?

The point in a titration at which the indicator changes is called the

irakobra [83]

Answer:

End point

Explanation:

The point at which the indicator changes color is called the endpoint. So the addition of an indicator to the analyte solution helps us to visually spot the equivalence point in an acid-base titration

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8 0

3 years ago

The total concentration of ions in a 0.75 M solution of HCl is

EastWind [94]

<h3>Answer:</h3>

The total concentration of ions in a 0.75 M solution of HCl is 1.5 M

That is; 0.75 M H⁺ and 0.75 M Cl⁻

<h3>Explanation:</h3>

Concentration or molarity is the number of moles of a compound or an ion contained in one liter of solution. It is measured in moles per liter (M).
The concentration of ions making a compound is determined by the ratio of moles of the compound and the constituents ions.

For instance, HCl dissociates to give H⁺ and Cl⁻

HCl(aq) → H⁺(aq) + Cl⁻(aq)

Therefore, since the mole ratio between HCl and the constituent ions H⁺ and Cl⁻ is 1:1, then 0.75 M of HCl dissociates to give 0.75 M H⁺ and 0.75 m Cl⁻

Hence the total concentration of ions in a 0.75 M solution of HCl is 1.5 M (0.75 M H⁺ and 0.75 M Cl⁻)

4 0

3 years ago

How many atoms of oxygen are in 0.100 mol of silicon dioxide?

lys-0071 [83]

1) Silicon dioxide formula: SiO2 ....... 2 is a subscript for the O atom

2) From the formula you have 1 molecula of SiO2 contains 1 atom of SiO2

3) Then, 0.100 mol of SiO2 contains 0.1 mol of Si

4) Multiply by Avogadro's number: 0.100mol * 6.022*10^23 atoms/mol= 6.02*10^22 atoms

Answer: 6.02*10^22 atoms

3 0

3 years ago

1. Use your knowledge of valence electrons and how they affect bonds to figure out how carbon (Group 14) and oxygen (Group 16) w

erik [133]

From the fact that oxygen is in group 16 and carbon is in group 14, the structure of CO2 must be O=C=O. In methane, there is no bond between any of the hydrogen atoms. The structure of H2O2 is H–O–O–H.

Carbon is in group 14 hence it has four valence electrons and oxygen is in group 16 hence it has six valence electrons. This implies that each oxygen atom will share four electrons with carbon in a covalent bond to form the structure O=C=O.

In CH4, we know that carbon is tetravalent so it forms for bonds. Therefore, there is no bond between hydrogen atoms so it bonds with each hydrogen atom; hydrogen only forms one bond.

In H2O2, there is the peroxide ion that has the structure O-O. Hence, the correct structure of H2O2 is H–O–O–H.

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