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3 years ago

Based on Chromium's position on the periodic table, which statement describes the element

Chemistry

1 answer:

natali 33 [55]3 years ago

7 0

Answer:

C. chromium is a metal that is less reactive than sodium.

Explanation:

Hello.

Given the options:

A. chromium is a nonmetal and therefore a good conductor of heat and electricity .

B. chromium is a metal that is more reactive than potassium .

C. chromium is a metal that is less reactive than sodium .

D. chromium is a noble gas that is not reactive.

In this case, since chromium is in period 4 group VIB we infer it is a transition metal which slightly reacts with acids and poorly reacts with oxygen and other oxidizing substances. Thus, in comparison with both sodium and potassium which are highly reactive even with water as they get on fire, we can say that it is less reactive than both potassium and sodium, therefore, answer is: C. chromium is a metal that is less reactive than sodium.

Best regards.

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ASAP

emmasim [6.3K]

Molar mass of SnO_2:-

$\\ \sf\longmapsto 118+2(16)=118+32=150g/mol$

Given mass=80.8g

$\\ \sf\longmapsto No\:of\;moles=\dfrac{Given\:mass}{Molar\:mass}$

$\\ \sf\longmapsto No\:of\;moles=\dfrac{80.8}{150}$

$\\ \sf\longmapsto No\:of\:moles=0.5mol$

1 mol of SnO_2 produces 2mol of water

0.5mol of SnO_2 will produce 0.5(2)=1mol of water

3 0

3 years ago

Balance the following skeleton reaction and identify the oxidizing and reducing agents: Include the states of all reactants and

kompoz [17]

Answer:

a. 2NO₂ (g) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + H₂O (l)

b. i. NO₂⁻ is the oxidizing agent

ii. NO₃⁻ is the reducing agent.

Explanation:

a. Balance the following skeleton reaction

The reaction is

NO₂ (g) → NO₃⁻ (aq) + NO₂⁻ (aq)

The half reactions are

NO₂ (g) → NO₃⁻ (aq) (1) and

NO₂ (g) → NO₂⁻ (aq) (2)

We balance the number of oxygen atoms in equation(1) by adding one H₂O molecule to the left side.

So, NO₂ (g) + H₂O (l) → NO₃⁻ (aq)

We now add two hydrogen ions 2H⁺ on the right hand side to balance the number of hydrogen atoms

NO₂ (g) + H₂O (l) → NO₃⁻ (aq) + 2H⁺ (aq)

The charge on the left hand side is zero while the total charge on the right hand side is -1 + 2 = +1. To balance the charge on both sides, we add one electron to the right hand side.

So, NO₂ (g) + H₂O (l) → NO₃⁻ (aq) + 2H⁺ (aq) + e⁻ (4)

Since the number of atoms in equation two are balanced, we balance the charge since the charge on the left hand side is zero and that on the right hand side is -1. So, we add one electron to the left hand side.

So, NO₂ (g) + e⁻ → NO₂⁻ (aq) (5)

We now add equation (4) and (5)

So, NO₂ (g) + H₂O (l) → NO₃⁻ (aq) + 2H⁺ (aq) + e⁻ (4)

+ NO₂ (g) + e⁻ → NO₂⁻ (aq) (5)

2NO₂ (g) + H₂O (l) + e⁻ → NO₃⁻ (aq) + NO₂⁻ (aq) + 2H⁺ (aq) + e⁻ (4)

2NO₂ (g) + H₂O (l) → NO₃⁻ (aq) + NO₂⁻ (aq) + 2H⁺ (aq)

We now add two hydroxide ions to both sides of the equation.

So, 2NO₂ (g) + H₂O (l) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + 2H⁺ (aq) + 2OH⁻ (aq)

The hydrogen ion and the hydroxide ion become a water molecule

2NO₂ (g) + H₂O (l) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + 2H₂O (l)

2NO₂ (g) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + H₂O (l)

So, the required reaction is

2NO₂ (g) + 2OH⁻ (aq) → NO₃⁻ (aq) + NO₂⁻ (aq) + H₂O (l)

b. Identify the oxidizing agent and reducing agent

Since the oxidation number of oxygen in NO₂ is -2. Since the oxidation number of NO₂ is zero, we let x be the oxidation number of N.

So, x + 2 × (oxidation number of oxygen) = 0

x + 2(-2) = 0

x - 4 = 0

x = 4

Since the oxidation number of oxygen in NO₂⁻ is -1. Since the oxidation number of NO₂⁻ is -1, we let x be the oxidation number of N.

So, x + 2 × (oxidation number of oxygen) = 0

x + 2(-2) = -1

x - 4 = -1

x = 4 - 1

x = 3

Also, the oxidation number of oxygen in NO₃⁻ is -1. Since the oxidation number of NO₃⁻ is -1, we let x be the oxidation number of N.

So, x + 2 × (oxidation number of oxygen) = -1

x + 3(-2) = -1

x - 6 = -1

x = 6 - 1

x = 5

i. The oxidizing agent

The oxidation number of N changes from +4 in NO₂ to +3 in NO₂⁻. So, Nitrogen is reduced and thus NO₂⁻ is the oxidizing agent

ii. The reducing agent

The oxidation number of N changes from +4 in NO₂ to +5 in NO₃⁻. So, Nitrogen is oxidized and thus and NO₃⁻ is the reducing agent.

3 0

3 years ago

How many grams of ethanol, CH3CH2OH, should you dissolve in water to make 0.800 L of vodka (which is an aqueous solution that is

Rashid [163]

Answer:

252.5g

Explanation:

Given parameters:

Volume of vodka = 0.8L

Molarity of ethanol = 6.86M

Unknown:

Mass of ethanol = ?

Solution:

Molarity is one of the ways of expressing concentration. It is the number of moles of a substance in a solution.

Since Vodka = ethanol + water = solution

Molarity = $\frac{number of moles of ethanol}{Volume of solution}$

Number of moles of ethanol = molarity of vodka x volume of solution

Once we obtain the number of moles, we can derive the mass of the ethanol;

Number of moles = 6.86M x 0.8L = 5.49moles

Mass of ethanol = number of moles x molar mass

molar mass of ethanol = 12 + 3(1) + 12 + 2(1) + 16 + 1 = 46g/mol

Mass of ethanol = 5.49 x 46 = 252.5g

3 0

4 years ago

You are carefully watching the temperature of your melting point apparatus as it is heating up. At 132 C it is still a white sol

Lisa [10]

Answer:

See the answer below

Explanation:

<em>Since the experiment is set out to determine the melting point of the white solid, after missing the melting point due to distraction, there are two possible solutions and both involves a repeat of the experiment.</em>

1. The first one is to allow the molten substance to solidify again and then repeat the experiment. This time around, a critical attention should be paid to be able to notice the melting point temperature once the temperature gets to 132 C.

2. The second solution would be discard the molten substance and repeat the experiment with the a new solid one. Similarly, critical attention should be paid once the temperature gets to 132 C since it is sure that the melting point lies within 132 and 138 C.

6 0

4 years ago

The ------------- the temperature of an object, the faster the molecules vibrate.

labwork [276]

Higher, they have more energy so they move faster

3 0

3 years ago

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