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3 years ago

!!!!HURRY!!!! What reaction is endothermic?

Chemistry

1 answer:

Alex3 years ago

4 0

Answer:

The reaction in which heat is absorbed from the surrounding is called endothermic reaction.

I think it's answer is 2nd option.

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Which of the following reactions is endothermic?

ohaa [14]

The answer is D

Hope that helps :)

-Asmaa Ghazzawi

4 0

4 years ago

Read 2 more answers

A) Compute the repeat unit molecular weight of polystyrene. B) Compute the number-average molecular weight for a polystyrene for

Andrej [43]

Answer:

Explanation:

In Polystrene, the molecular formula for the repeat unit = $C_8H_8$ ;

and the atomic weights of Carbon C = 12.01 g/mol

For Hydrogen, it is 1.01 g/mol

Hence, the repeat unit molecular weight is:

m = 8 (12.01 g/mol)+8(1.01 g/mol)

m = 96.08 g/mol + 8.08 g/mol

m = 104.16 g/mol

The degree of polymerization = no-average molecular weight/repeat unit molecular weight.

Mathematically;

$DP = \dfrac{\overline M_n}{m}$

$\overline M_n= DP \times m$

$\overline M_n= 25000 \times 104.16 \ g/mol$

$\overline M_n= 2604000 \ g/mol$

7 0

3 years ago

Why do you think different liquids have different freezing points

Ganezh [65]

I think that different liquids have different freezing points because every liquid consists of different atoms and different things that make up the atom causing them to have different freezing points.

5 0

3 years ago

How many grams of CO are produced when 41.0 g of C reacts?

CaHeK987 [17]

Answer:

95.7 g CO to the nearest tenth.

Explanation:

2C + O2 ---> 2CO

Using relative atomic masses:

24 g C produces 2*12 + 2*16 g CO.

So 41 g produces ( (2*12 + 2*16) * 41 ) / 24

= 95.7 g CO,

7 0

3 years ago

Show your work with good use of units, rounding, and significant figures. [Hint: it is good practice to show the value of your a

mel-nik [20]

Heat required : 4.8 kJ

<h3>Further explanation </h3>

The heat to change the phase can be formulated :

Q = mLf (melting/freezing)

Q = mLv (vaporization/condensation)

Lf=latent heat of fusion

Lv=latent heat of vaporization

The heat needed to raise the temperature

Q = m . c . Δt

1. heat to raise temperature from -20 °C to 0 °C

$\tt Q=10\times 2.09\times (0-(-20)=418~J$

2. phase change(ice to water)

$\tt Q=10\times 333=3330~J$

3. heat to raise temperature from 0 °C to 25 °C

$\tt Q=10\times 4.18\times (25-0)=1045~J$

$\tt Q~tot=418+3330+1045=4793~J\rightarrow rounding~and~2~sig~figs=4.8~kJ$

3 0

3 years ago