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3 years ago

Find the discriminant and the number of real roots for this equation. x2 + 2x+8 = 0

Chemistry

1 answer:

adell [148]3 years ago

3 0

Answer:

Option 'D' is correct.

Step-by-step explanation:

Since we have given that

We will first find the "Discrimination":

Since discriminant is less than 0 i.e. D<0.

So, there will no real roots.

Hence, D = -28 and there is no real roots.

Therefore, Option 'D' is correct.

Explanation:

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3 points Given 0.65 moles KNO3: (a) Convert to grams (b) Convert to particles.

Vlad [161]

Answer: Convert to grams

Explanation:

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3 years ago

How does the A Hreaction relate to the A He of molecules involved in a reaction?

igor_vitrenko [27]

Answer:

B. ΔHreaction = ΔH°f reactants- ΔH°f products

Explanation:

Using Hess's law, it is possible to sum ΔH of several related reactions to find ΔH of a particular reaction.

Having in mind Hess's law, ΔH°f is defined as the change in enthalpy during the formation of 1 mole of substance from its constituent elements (That is, pure elements, mono or diatomics, that have a ΔH° = 0).

For example, in ΔH°f of H₂O, the equation is:

H₂(g) + 1/2O₂(g) → H₂O(g)

The constituent elements with ΔH°f = 0 are H₂(g) and O₂(g).

Now, using Hess's law, you can sum the ΔH°f of substance in a reaction as, for example:

NaOH + HCl → H₂O + NaCl. ΔHr

The ΔH°f for each substance in the reaction is:

NaOH: Na + 1/2H₂ + 1/2O₂ → NaOH (1)

HCl: 1/2H₂ + 1/2Cl₂ → HCl (2)

H₂O: H₂ + 1/2O₂ → H₂O (3)

NaCl: Na + 1/2Cl₂ → NaCl (4)

The algebraic sum of (3) + (4) is -(ΔH°f reactants):

H₂ + 1/2O₂ + Na + 1/2Cl₂ → NaCl + H₂O ΔH°f reactants

This reaction - {(1)+(2)} ΔH°f products

NaOH + HCl → H₂O + NaCl.

ΔHr = ΔH°f reactants- ΔH°f products

In the example, we obtain this relationship that can be expanded for all reactions. Thus, right answer is:

<h3>B. ΔHreaction = ΔH°f reactants- ΔH°f products</h3>

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3 years ago

In what can wax harmful

Tanzania [10]

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6 0

3 years ago

Solid cadmium sulfide reacts with an aqueous solution of sulfuric acid . Express your answer as a balanced chemical equation. Id

max2010maxim [7]

Explanation:

When solid cadmium sulfide reacts with an aqueous solution of sulfuric acid then the reaction will be as follows.

$CdS(s) + H_{2}SO_{4}(aq) \rightarrow CdSO_{4}(aq) + H_{2}S(g)$

Hence, ionic equation for this reaction is as follows.

$CdS(s) + 2H^{+}(aq) + SO^{2-}_{4}(aq) \rightarrow Cd^{2+}(aq) + SO^{2-}_{4}(aq) + H_{2}S(g)$

Therefore, net ionic equation for this reaction is as follows.

$CdS(s) + 2H^{+}(aq) \rightarrow Cd^{2+}(aq) + H_{2}S(g)$

8 0

3 years ago

Calculate the molality of a 5.73 M ethanol (C2H5OH) solution whose density is 0.9327 g/mL.

Natalka [10]

Answer:

Molality = 8.57 m

Explanation:

Given data:

Molarity of solution = 5.73 M

density = 0.9327 g/mL

Molality of solution = ?

Solution:

Molality = moles of solute / kg of solvent.

Kg of solvent:

Mass of 1 L solution = density× volume

Mass of 1 L solution = 0.9327 g/mL × 1000 mL

Mass of 1 L solution = 932.7 g

Mass of solute:

Mass of 1 L = number of moles × molar mass

Mass = 5.73 mol × 46.068 g/mol

Mass = 263.97 g

Mass of solvent:

Mass of solvent = mass of solution - mass of solute

Mass of solvent = 932.7 g - 263.97 g

Mass of solvent = 668.73 g

In Kg = 668.73 /1000 = 0.6687 Kg

Molality:

Molality = number of moles of solute / mass of solvent in Kg

Molality = 5.73 mol / 0.6687 Kg

Molality = 8.57 m

4 0

2 years ago