21. A good transition state analog

BigorU [14]

Answer:

Samarium

Explanation:

The element Sm describe is called Samarium. This element has unique sets of properties that makes it very unique and distinct.

The lanthanides are found in the f-block on the periodic table of elements.

This element is a moderately hard silvery metal that readily oxidizes in air. It assumes an oxidation state of +3. The element has an atomic number of 62

7 0

3 years ago

Calculate the standard reaction enthalpy for the reaction NO2(g) → NO(g) + O(g) given +142.7 kJ/mol for the standard enthalpy of

bulgar [2K]

Answer:

The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.

Explanation:

$O_2(g) \rightarrow \frac{2}{3}O_3(g),\Delta H^o_{1}=142.7 kJ/mol$ ..[1]

$O_2(g) \rightarrow 2 O(g),\Delta H^o_{2}=498.4 kJ/mol$ ..[2]

$NO(g) + O_3(g)\rightarrow NO_2(g) + O_2(g) ,\Delta H^o_{3} = -200 kJ/mol$ ..[3]

$NO_2(g)\rightarrow NO(g) + O(g),\Delta H^o_{4}=?$ ..[4]

Using Hess's law:

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

2 × [4] = [2]- (3 ) × [1] - (2) × [3]

$2\times \Delta H^o_{4}=\Delta H^o_{2} -3\times \Delta H^o_{1}-2\times \Delta H^o_{3}$

$2\times \Delta H^o_{4}=498.4 kJ/mol-3\times 142.7 kJ/mol-2\times -200 kJ/mol$

$2\times \Delta H^o_{4}=470.3 kJ/mol$

$\Delta H^o_{4}=\frac{470.3 kJ/mol}{2}=235.15 kJ/mol$

The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.

7 0

3 years ago

1. Consider the following equilibrium system: C(s) + CO2(g) 2CO(g)

ser-zykov [4K]

Answer:

a) equilibrium shifts towards the right

b) equilibrium shifts towards the right

c) equilibrium shifts towards the left

d) has no effect on equilibrium position

e) has no effect on equilibrium position

Explanation:

A reversible reaction may attain equilibrium in a closed system. A chemical system is said to be in a state of dynamic equilibrium when the rate of forward reaction is equal to the rate of reaction.

According to Le Chateliers principle, when a constraint such as a change in temperature, pressure, volume or concentration is imposed upon a system in equilibrium, the equilibrium position shifts in such a way as to annul the constraint.

When the concentration of reactants is increased, the equilibrium position is shifted towards the right hand side and more products are formed. For an endothermic reaction, the reverse reaction is favoured by a decrease in temperature. Increase in pressure has no effect on the system since there are equal volumes on both sides of the reaction equation. Similarly, the addition of a catalyst has no effect on the equilibrium position since it speeds up both the forward and reverse reactions to the same extent.

3 0

3 years ago

Which two solutions would be the BEST choice for their experiment?

Margaret [11]

Solutions 1 and 3 because they are strong acids and a strong base. <u>Option A.</u>

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Strong acids and strong bases are completely ionized in an aqueous solution. Weak acids and weak bases also ionize, but only partially and the reaction is reversible. So you know if an acid or base is strong or weak. A simple way to determine strength is to add the acid or base to water. A higher reactivity means a stronger acid or base.

One of the simplest tests to determine whether a solution is an acid or base is the litmus paper test. To do this, dip a special strip of paper so-called litmus paper into the solution and observe the color of the paper. Litmus paper turns red in acidic solutions and blue in basic solutions. Sodium hydroxide is the strongest base because it completely dissociates to form sodium and hydroxide ions. These hydroxide ions are further treated with hydrogen ions by an acid to completely ionize the hydrogen ions.

Learn more about Experiment here:-https://brainly.ph/question/672153

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5 0

1 year ago

Why is staining useful when studying cells through a microscope

Gemiola [76]

It's useful because it highlights structures in biological tissue.

8 0

3 years ago