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3 years ago

HELP!!!! please omg

Chemistry

1 answer:

OverLord2011 [107]3 years ago

7 0

Answer:

I believe it's A. to reduce air bubbles. Tbh, it's been a while

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Consider only the experiment you conducted with 0.5 g. of lactose.

rjkz [21]

Answer is: the pH value(level) is the independent variable.

Missing question: We conducted an experiment where we added 0.5 g of lactose to 5 different test tubes all containing 5 different pH levels. What is the independent variable?
In this experiment pH level changes, so results depend on different pH values.
Mass of lactose is same during experiment,so the number of molecules of product formed per minute is the dependent variable.

8 0

4 years ago

A pharmacist wishes to strengthen a mixture from 10%alcohol to 30% alcohol. How much pure alcohol should be added to 7 liters of

Tomtit [17]

Answer:

2 litres of pure alcohol will be added to make the overall concentration of 9 litres of mixture as 30%.

Explanation:

Suppose x is the number of litres added to the 10% mixture than the quantity of new mixture is given as below

$n_{old}=7$ litres
$n_{new}=7+x$ litres

Also the quantity of alcohol is given as

$q_{old}=10 \% \, of \, 7 \, litres =0.7$

$q_{added}=x$

$q_{new}= 30 \% \,of \,new\, quantity = 0.3(7+x)$

Now the equation is as

$q_{old}+q_{added}=q_{new}\\0.7+x=0.3(7+x)\\0.7+x=2.1+0.3x\\x-0.3x=2.1-0.7\\0.7x=1.4\\x=2 \, litres$

So 2 litres of pure alcohol will be added to make the overall concentration of 9 litres of mixture as 30%.

8 0

3 years ago

Suppose you put a whole antacid tablet in one glass of water and a crushed antacid tablet in another glass containing the same a

iogann1982 [59]

The crushed tablets would stop bubbling/fuzzing first because it has a smaller surface area which means that it would dissolve before the uncrushed tablets which has a larger surface area.

3 0

3 years ago

Assuming that gasoline is 100% isooctane, that isooctane burns to produce only CO2CO2 and H2OH2O, and that the density of isooct

Aleksandr [31]

Answer:

1.12×10¹¹ kg of CO₂ are produced with 4.6×10¹⁰ L of isooctane

Explanation:

Let's state the combustion reaction:

C₈H₁₈ + 25/2O₂ → 8CO₂ + 9H₂O

Let's calculate the mass of isooctane that reacts.

Density = Mass / Volume

Density . Volume = Mass

First of all, let's convert the volume in L to mL, so we can use density.

4.6×10¹⁰ L . 1000 mL / 1L = 4.6×10¹³ mL

0.792 g/mL . 4.6×10¹³ mL = 3.64 ×10¹³ g

This mass of isooctane reacts to produce CO₂ and water, so let's determine the moles of reaction

3.64 ×10¹³ g . 1mol / 114 g = 3.19×10¹¹ mol

Ratio is 1:8 so 1 mol of isooctane can produce 8 moles of dioxide

Therefore 3.19×10¹¹ mol would produce (3.19×10¹¹ mol . 8) = 2.55×10¹² moles of CO₂

Now, we can determine the mass of produced CO₂ by multipling:

moles . molar mass

2.55×10¹² mol . 44 g/mol = 1.12×10¹⁴ g of CO₂

If we convert to kg 1.12×10¹⁴ g / 1000 = 1.12×10¹¹ kg

6 0

3 years ago

What is physical since ?

uysha [10]

You mean physical science?

3 0

2 years ago

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