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3 years ago

13

How much heat, in kJ, will be absorbed by a 25.0 g piece of aluminum (specific heat = 0.930 J/g･°C) as it changes temperature fr

om 25.0°C to 76.0°C?

1 answer:

faust18 [17]3 years ago

4 0

Answer:

quantity of heat=mc*theta

=25*0.930(76-25)

=25*0.930*51

=1185.75J

=11.9kJ

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Classify each element as a metal, nonmetal, or semimetal. br in cr ca drag the appropriate items to their respective bins. view

goldenfox [79]

Below is the distribution of given elements and additional elements in their respective bins.

Iron, Magnesium, Aluminium, Calcium, Chromium and Indium are classified as Metals due to their hardness, conduction of current and heat, Solid state, formation of metallic bonding and prefers to form cations e.t.c

Oxygen, Neon and Bromine are classified as non-metals. Non-metals are mostly gases except for Bromine. They are highly volatile and prefers to form anions.

Semimetals are those metals which have both properties of metals and non-metals and are also called as metalloids.

6 0

3 years ago

NH4NO3, whose heat of solution is 25.7 kJ/mol, is one substance that can be used in cold pack. If the goal is to decrease the te

makvit [3.9K]

Answer:

There are necessaries 35,2g of NH₄NO₃ per 100,0g of water to decrease the temperature of the solution from 25,0°C to 5,0°C

Explanation:

To decrease the temperature of the solution there are necessaries:

4,184J/g°C×(5,0°C-25,0°C)×(100,0g+X) = -Y

8368J + 83,68J/gX = Y <em>(1)</em>

Where x are grams of NH₄NO₃ you need to add and Y is the energy that you need to decrease the heat.

Also, the energy Y will be:

Y = 25700J/mol× $\frac{1mol}{80,043g}$ X

Y = 321J/g X <em>(2)</em>

Replacing (2) in (1)

8368J + 83,68J/g X = 321J/g X

8363J = 237,32J/gX

<em>X = 35,2g</em>

<em />

Thus, there are necessaries 35,2g of NH₄NO₃ per 100,0g of water to decrease the temperature of the solution from 25,0°C to 5,0°C

I hope it helps!

6 0

3 years ago

All of the substances on the periodic table are classified as elements except

zzz [600]

Answer: all elements in the periodic table is classified as elements

Explanation:

The structure of the table shows periodic trends. The seven rows of the table, called periods, generally have metals on the left and nonmetals on the right. The columns, called groups, contain elements with similar chemical behaviours. Six groups have accepted names as well as assigned numbers: for example, group 17 elements are the halogens; and group 18 are the noble gases

6 0

3 years ago

A 2.0 molal sugar solution has approximately the same freezing point as 1.0 molal solution of 1) CaCl2 2) CH3COOH 3) NaCl 4) C2H

sertanlavr [38]

Answer:

3) NaCl.

Explanation:

<em>∵ ΔTf = iKf.m</em>

where, <em>i</em> is the van 't Hoff factor.

<em>Kf </em>is the molal depression freezing constant.

<em>m</em> is the molality of the solute.

<em>The van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass. </em>

<em></em>

For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1.

<em>So, for sugar: i = 1.</em>

<em>∴ ΔTf for sugar = iKf.m = (1)(Kf)(2.0 m) = 2 Kf.</em>

<em></em>

For most ionic compounds dissolved in water, the van 't Hoff factor is equal to the number of discrete ions in a formula unit of the substance.

For NaCl, it is electrolyte compound which dissociates to Na⁺ and Cl⁻.

<em>So, i for NaCl = 2.</em>

<em>∴ ΔTf for NaCl = iKf.m = (2)(Kf)(1.0 m) = 2 Kf.</em>

<em></em>

<em>So, the right choice is: 3) NaCl.</em>

<em></em>

8 0

3 years ago

Help me due tomorrow :,)

lesya [120]

#a

Zinc displaces copper

It means

Zinc is more reactive than copper

#b

Zinc+Copper sulphate--> Zinc sulphate+Copper

#c

No reaction because

Magnesium is more reactive than zinc

#d

Reaction occurs

Iron is more reactive than copper
Magnesium is more reactive than iron

Order:-

Cu<Fe<Zn<Mg

3 0

3 years ago