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2 years ago

15

How much heat is released when 35kg of water freezes?

1 answer:

inn [45]2 years ago

3 0

You need an additional point of data here: the enthalpy of fusion, or conversely the enthalpy of melting (they differ only by their sign). For water (or ice) that value is gotten from sources such as the internet

<span>ΔH°(fus) = 6.01 kJ/mole </span>

<span>Since you have 35 000g, how many moles do you have? </span>
<span>Moles H2O = 35000 g/(18.015 g/mole) = 1942.8 moles</span>

<span>So, take that ΔH°(fus) in kJ/mole, multiply by the number of moles, and there ya go!
</span>
6.01 x 1942.8 = 11,676 kJ of energy is released

Hope I helped!! xx

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Thylakoids contain chlorophyl that absorb solar energy

steposvetlana [31]

Answer:

True

True statement:

Because pigment molecules absorb solar energy and thylakoids are pigment molecules

3 0

2 years ago

The period of rotation of Mars is 1 day and 37 minutes. Determine its frequency of rotation in Hertz.

Sholpan [36]

The frequency of rotation of Mars is 0.0000113 Hertz.

<u>Given the following data:</u>

Period = 1 day and 37 minutes.

To find the frequency of rotation in Hertz:

First of all, we would convert the the value of period in days and minutes to seconds because the period of oscillation of a physical object is measured in seconds.

<u>Conversion:</u>

1 day = 24 hours

24 hours to minutes = $60$ × $24$ = $1440$ minutes

$1440 + 37 = 1477 \; minutes$

1 minute = 60 seconds

1477 minute = X seconds

Cross-multiplying, we have:

$X = 60$ × $1477$

X = 88620 seconds

Now, we can find the frequency of rotation of Mars by using the formula:

$Frequency = \frac{1}{Period}\\\\Frequency = \frac{1}{88620}$

<em>Frequency </em><em>of rotation</em> = <em>0.0000113 Hertz</em>

Therefore, the frequency of rotation of Mars is 0.0000113 Hertz.

Read more: brainly.com/question/14708169

8 0

2 years ago

Thomas and John are carrying a 43kg cylinder head on a 510cm X 510mm board. The cylinder head with dimensions of 43cm X 250mm li

tatyana61 [14]

John carry the heaviest load.

<h3>How to find out who is carrying the heavy load?</h3>

Write down given data from questions:

Board=510cm X 510mm.

Cylinder head with dimensions=43cm X 250mm.

Cylinder lies across the board 210cm from john.

Find out: Who is carry the heaviest load?

Calculation:

We assume that mass of cylinder head = x kg

Then weight=x x 9*81

W=9.81x Newton.

Weight per unit length= Weight/Total leanth

Weight per unit length= 9.81x/43

(w/l)=0.23x N/cm

From equation contition: $(F_{J} +F_{T} =9.81x n)$

$F_{T} (510)=9.81x$ (210+21.5)

$F_{T} (510)=9.81 x (231.5)$

$F_{T} =4.452x N.$

$F_{J} =9.81x-4.452x$

$F_{J} =5.358 xN$

Therefore $F_{J} \geq F_{T}$

To learn more about mass per unit length, refer to:

brainly.com/question/24180692

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4 0

1 year ago

A projectile is launched vertically at 100 m/s. If air resistance can be ignored, at what speed will it return to its initial le

eduard

<h2>Speed with which it return to its initial level is 100 m/s</h2>

Explanation:

We have equation of motion v² = u² + 2as

Initial velocity, u = 100 m/s

Acceleration, a = -9.81 m/s²

Final velocity, v = ?

Displacement, s = 0 m

Substituting

v² = u² + 2as

v² = 100² + 2 x -9.81 x 0

v² = 100²

v = ±100 m/s

+100 m/s is initial velocity and -100 m/s is final velocity.

Speed with which it return to its initial level is 100 m/s

7 0

2 years ago

Read 2 more answers

If 10 waves pass a point each second and their wavelength is 30m, what is their speed?

svet-max [94.6K]

Answer:

300m/s

Explanation:

velocity = frequency(wavelength)

Since 10 waves pass a point each second, frequency is 10

therefore, speed = (10)(30 = 300m/s

5 0

3 years ago