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3 years ago

a substance that undergoes a physical change like melting is still the same substance is it true or false

Chemistry

2 answers:

Jlenok [28]3 years ago

6 0

Answer:This is true

Explanation:

Its true because its chemical composition stays the same

Juli2301 [7.4K]3 years ago

3 0

the answer would be true

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Butoxors [25]

I think it’s The second option sorry if I’m wrong

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3 years ago

Consider the reaction 2 al + Fe2O3 to 2Fe + Al2O3. If 60.0g of Al is reacted with excess Fe2O3, determine the amount (in moles)

olganol [36]

The amount of Al2O3 in moles= 1.11 moles while in grams = 113.22 grams

calculation

2 Al + Fe2O3 → 2Fe + Al2O3

step 1: find the moles of Al by use of moles= mass/molar mass formula

= 60.0/27= 2.22 moles

Step 2: use the mole ratio to determine the moles of Al2O3.

The mole ratio of Al : Al2O3 is 2: 1 therefore the moles of Al2O3= 2.22/2=1.11 moles

Step 3: finds the mass of Al2O3 by us of mass= moles x molar mass formula.

The molar mass of Al2O3 = (2x27) +( 16 x3) = 102 g/mol

mass is therefore= 102 g/mol x 1.11= 113.22 grams

7 0

3 years ago

Let us write the appropriate equilibria and associate the correction <img src="https://tex.z-dn.net/?f=K_b" id="TexFormula1" tit

rosijanka [135]

Explanation:

The relation between $K_a\&K_b$ is given by :

$K_w=K_a\times K_b$

Where :

$K_w=1\times 10^{-14}$ = Ionic prodcut of water

The value of the first ionization constant of sodium sulfite = $K_{a1}=1.4\times 10^{-2}$

The value of $K_{b1}$ :

$1\times 10^{-14}=1.4\times 10^{-2}\times K_{b1}$

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The value of $K_{b2}$ :

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$K_{b1}=\frac{1\times 10^{-14}}{6.3\times 10^{-8}}=1.6\times 10^{-7}$

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3 years ago

During normal, relaxed respiration, about 500ml of air enters and leaves the lungs with each respiratory cycle. this is called t

Marianna [84]

During normal respiration, about 500ml of air enters and leaves the lungs with each respiratory cycle. This is called the tidal volume.

When a person is relaxed, the normal amount of air such a person breathes in and out is called the tidal volume. It is usually measured in millimeters. For the average adult male, it is 500ml, and the tidal volume of average adult female 400ml.

In order to regulate oxygen intake and expulsion of carbon dioxide, the lungs act as buffers in order to absorb the maximum amount of oxygen possible for respiration and other metabolic functions in the body.

When the tidal volume is above or below the 500ml mark, it could signal the presence of underlying pathological conditions like bronchitis, emphysema and asthma.

To find out more about tidal volume, visit:

brainly.com/question/17439101

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1 year ago

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miv72 [106K]

The problem applies Charles' law since constant pressure with varying volume and temperature are given. Assuming ideal gas law, the equation to be used is $\frac{ V_{1} }{ T_{1} }$ = $\frac{ V_{2} }{ T_{2} }$ . We make sure the temperatures are expressed in Kelvin, hence the given added with 273. The volume 2 is equal to 25.2881 liters.

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3 years ago

Read 2 more answers

a substance that undergoes a physical change like melting is still the same substance is it true or false​

a substance that undergoes a physical change like melting is still the same substance is it true or false