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NeTakaya
3 years ago
11

A chemist is trying to classify an unknown substance as either a metal or nonmetal. What question should the chemist use to help

classify the material?
a.Is the material a good conductor or a poor conductor?
b.Does the material feel rough or smooth?
c.Does the material feel hard to the touch?
d.Will the material float in water?
Chemistry
1 answer:
Papessa [141]3 years ago
5 0

Answer:

A

Explanation:

A: Metals are ofthen the best conductors.

B: Metals and non-metals can be smooth or rough

C: Metals and non-metals can be hard to the touch

D: Metals and non-metals can float in water

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URGENT!!!!!!
Marrrta [24]

Answer:

(a) 0.0301g

Explanation:

4 0
3 years ago
For the reaction KClO2⟶KCl+O2 KClO2⟶KCl+O2 assign oxidation numbers to each element on each side of the equation. K in KClO2:K i
frosja888 [35]

Answer:

Explanation:

The formula of the reaction:

            KClO₂ → KCl + O₂

To assign oxidation numbers, we have to obey some rules:

  1. Elements in an uncombined state or one whose atoms combine with one another to form molecules have an oxidation number of zero.
  2. The charge on simple ions signifies their oxidation number.
  3. The algebraic sum of all the oxidation number of all atoms in a neutral compound is zero. For radicals with charges, their oxidation number is the charge.

The oxidation number of K in KClO₂:

                                   K + (-1) + 2(-2) = 0

                                    K-5 = 0

                                    K = +5

The oxidation number of K in KCl:

                                K + (-1) = 0

                                K = +1

The oxidation number Cl in KClO₂ is -1

For Cl in KCl, the oxidation number is -1

For O in KClO₂, the oxidation number is (2 x -2) = -4

For O in O₂, the oxidation number is 0

K moves from an oxidation state of +5 to +1. This is a gain of electrons and K has undergone reduction. We then say K is reduced.

O moves from an oxidation state of -4 to 0. This is a loss of electrons and O has undergone oxidation. We say O is oxidized.

7 0
3 years ago
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If the same amount of heat is added to 25.0 g of each of the metals, which are all at the same initial temperature, which metal
AVprozaik [17]

Answer:

The bismuth sample.

Explanation:

The specific heat c of a substance (might not be a metal) is the amount of heat required for heating a unit mass of this substance by unit temperature (e.g., \rm 1\; ^{\circ}C.) The formula for specific heat is:

\displaystyle c = \frac{Q}{m \cdot \Delta T},

where

  • Q is the amount of heat supplied.
  • m is the mass of the sample.
  • \Delta T is the increase in temperature.

In this question, the value of Q (amount of heat supplied to the metal) and m (mass of the metal sample) are the same for all four metals. To find \Delta T (change in temperature,) rearrange the equation:

\displaystyle c \cdot \Delta T = \frac{Q}{m},

\displaystyle \Delta T = \frac{Q}{c \cdot m}.

In other words, the change in temperature of the sample, \Delta T can be expressed as a fraction. Additionally, the specific heat of sample, c, is in the denominator of that fraction. Hence, the value of the fraction would be the largest for sample with the smallest specific heat.

Make sure that all the specific heat values are in the same unit. Find the one with the smallest specific heat: bismuth (\rm 0.123 \; J \cdot g\cdot \,^{\circ}C^{-1}.) That sample would have the greatest increase in temperature. Since all six samples started at the same temperature, the bismuth sample would also have the highest final temperature.

3 0
3 years ago
Mercury(II) oxide (HgO) decomposes to form mercury (Hg) and oxygen (O2). The balanced chemical equation is shown below.
zavuch27 [327]

15.63 mol. You need 15.63 mol HgO to produce 250.0 g O_2.

<em>Step 1</em>. Convert <em>grams of O_2 to moles of O_2</em>

Moles of O_2 = 250.0 g O_2 × (1 mol O_2/32.00 g O_2) = 7.8125 mol O_2

<em>Step 2</em>. Use the molar ratio of HgO:O_2 to convert <em>moles of O_2 to moles of HgO </em>

Moles of HgO = 0.8885 mol O_2 × (2 mol HgO/1 mol O_2) = <em>15.63 mol HgO</em>

7 0
3 years ago
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The reason it takes so much heat to melt ice or evaporate water is that extra energy is required to break _______ bonds between
mart [117]

It takes so much heat to melt ice or evaporate water because extra energy is required to break the hydrogen bonds between water molecules.

<h3>Hydrogen bond</h3>

Hydrogen bonding is an electrostatic force of attraction between a hydrogen atom found between a pair of other atoms having a high affinity for electrons.

Hydrogen bonds cause water to be exceptionally attracted to each other creating cohesion.

It takes so much heat to melt ice or evaporate water because extra energy is required to break the hydrogen bonds between water molecules.

Find out more on Hydrogen bond at: brainly.com/question/12798212

4 0
2 years ago
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