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3 years ago

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HELP ME!! THANH YOU If an atom has 80 protons and 121 neutrons, and is not in an excited state, how many electrons would Bohr sa

y the atom has? Select one: a. 41 b. 201 c. 121 d. 80

1 answer:

wariber [46]3 years ago

5 0

I think it might be 80

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The specific heat of copper metal is 0. 385 J/(g °C). How much energy must be added to a 35. 0-gram sample of copper to change t

Rus_ich [418]

The amount of heat required for changing the temperature of copper has been 606 J. Thus, option B is correct.

Specific heat has been defined as the amount of heat required to raise the temperature of 1 gram of substance by 1 degree Celsius.

The heat required to raise the temperature has been expressed as:

$\rm Heat=mass\;\times\;specific\;heat\;\times\;Change\;in\;temperature$

<h3>Computation for the heat energy required</h3>

The given specific heat of copper has been $\rm 0.385\;J/g^\circ C$

The mass of copper has been, $\rm 35\;g$

The initial temperature of copper has been, $\rm 20^\circ C$

The final temperature of copper has been, $\rm 65^\circ C$

The change in temperature has been, $\Delta T$

$\Delta T=\text{Final\;temperature-Initial\;temperature}\\\Delta T =65^\circ \text C-20^\circ \text C\\\Delta T=45^\circ \text C$

Substituting the values for the heat required as:

$\rm Heat=35\;g\;\times\;0.385\;J/g^\circ C\;\times\;45^\circ C\\Heat=606\;J$

The amount of heat required for changing the temperature of copper has been 606 J. Thus, option B is correct.

Learn more about specific heat, here:

brainly.com/question/2094845

7 0

2 years ago

How can indicator be used to determine if a solution is an acid or base

dalvyx [7]

Answer:

To tell if something is an acid or a base, you can use a chemical called an indicator. An indicator changes color when it encounters an acid or base. There are many different types of indicators, some that are liquids and others that are concentrated on little strips of "litmus" paper.

Explanation:

8 0

3 years ago

In a reaction vessel, 17.6 g of solid chromium(III) oxide, Cr2O3, was allowed to react with excess carbon tetrachloride in the f

notsponge [240]

Answer:

72.53% is the yield of CrCl3

Explanation:

Given

Reaction:

Cr2O3(s) + 3 CCl4(l) → 2 CrCl3(s) + 3 COCl2(aq)

CCl4 is in excess and 17.6g Cr2O3 present

The reaction yields 26.6g of CrCl3

To Find:

% yields of the reaction

Also given

Molar mass of CrCl3 = 158.35g/mol

Molar mass of Cr2O3 = 152.00 g/mol

By the stoichiometry of the reaction

1 mole of Cr2O3 gives 2 moles of CrCl3

0r

1 x1 52 g of Cr2O3 gives 2x 158.35 g of CrCl3

= 1 52 g of Cr2O3 gives 316.70 g of CrCl3

17.6 g of Cr2O3 gives (17.6÷152) × 316.70 g CrCl3

= 36.67 g CrCl3

but actual yield is only 26.6g

so % yield is (26.6 ÷÷ 36.67) × 100

= 72.53% is the yield of CrCl3

8 0

3 years ago

Why do Group 12 elements have different properties than Group 13<br> elements?

blagie [28]

Group 12 Elements have two valence electrons while Group 13 Elements have three valence electrons.
Number of valence electrons tend to determine factors like reactivity. So elements with different number of valence electrons will have different properties.
That is why G12 and G13 have different properties

6 0

3 years ago

What is the temperature change in 355 mL of water upon absorption of 34 kJ of heat? (The specific heat capacity of water is 4.18

frozen [14]

The temperature change is 23 °C.

<em>q = mC</em>Δ<em>T</em>

Δ<em>T</em> = <em>q</em>/(<em>mC</em>)

<em>m</em> = 355 g

∴ Δ<em>T</em> = (34 000 J)/(355 g × 4.184 J·°C⁻¹g⁻¹) = 23 °C

<em>Note</em>: The answer can have only <em>two significant figures</em> because that is all you gave for the amount of heat absorbed.

7 0

3 years ago

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