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3 years ago

In a convection current, what causes the molten rock to move from the bottom of the mantle to the top of the mantle?

1 answer:

6 0

pressure. but if you are in middle school then look in your textbook for all of your answers it will help you so much more than the internet.

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Explain how acid–base indicators can be used to determine the approximate pH of a substance.

mezya [45]

PH stands for potential hydrogen.
pH can be accurately tested using acid-based indicators since it is a part of the pH of something itself. (acid and bases) The indicators themselves work when the acidic properties of the indicator begins to dissolve and form ions which gives the color indicating the pH.

5 0

3 years ago

Melatonin has the chemical formula C13H16N2O2. Less than 10 milligrams(0.01g) Convert the melatonin to moles

oee [108]

Answer: There are 0.000043 moles of melatonin.

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

given mass = 10 mg = 0.01 g

molar mass of $C_{13}H_{16}N_2O_2$ = 232.28 g

${\text {moles of melatonin}}=\frac{0.01g}{232.28g/mol}=0.000043moles$

Thus there are 0.000043 moles of melatonin

6 0

3 years ago

In a synthesis reaction you start with 1.7L of Hydrogen how many liters of water will be produced?

jolli1 [7]

15.3 litres of water will be produced if we take 1.7 litres of Hydrogen

Explanation:

Let's take a look over synthesis reaction;

$H_{2}+ O_{2}$ $H_{2}O$

Balancing the chemical reaction;

$2H_{2} +O_{2}$ $2H_{2}O$

Thus, 2 moles of hydrogen molecules are required to form 2 moles of water molecules.

Equating the molarity;

$\frac{1.7*1}{2*2}$ = $\frac{x*1}{2*18}$

(Since, the molecular mass of hyd and water is 2 and 18 respectively)

x= $\frac{1.7*2*18}{2*2}$

x= 15.3 litres.

Thus,15.3 L of water will be produced if we take 1.7 litres of Hydrogen in a synthesis reaction.

6 0

3 years ago

What is the definition of bond?

JulijaS [17]

Join or be joined securely to something else, typically by means of an adhesive substance, heat, or pressure.

3 0

3 years ago

If you place 1.0 L of ethanol (C2H5OH) in a small laboratory that is 3.0 m long, 2.0 m wide, and 2.0 m high, will all the alcoho

ankoles [38]

If you place 1.0 L of ethanol (C2H5OH) in a small laboratory that is 3.0 m long, 2.0 m wide, and 2.0 m high, will all the alcohol evaporate? If some liquid remains, how much will there be? The vapor pressure of ethyl alcohol at 25 °C is 59 mm Hg, and the density of the liquid at this temperature is 0.785g/cm^3 .

will all the alcohol evaporate? or none at all?

Answer:

Yes, all the ethanol present in the laboratory will evaporate since the mole of ethanol present in vapor is greater. The volume of ethanol left will therefore be zero.

Explanation:

Given that:

The volume of alcohol which is placed in a small laboratory = 1.0 L

Vapor pressure of ethyl alcohol at 25 ° C = 59 mmHg

Converting 59 mmHg to atm ; since 1 atm = 760 mmHg;

Then, we have:

= $\frac{59}{760}atm$

= 0.078 atm

Temperature = 25 ° C

= ( 25 + 273 K)

= 298 K.

Density of the ethanol = 0.785 g/cm³

The volume of laboratory = l × b × h

= 3.0 m × 2.0 m × 2.5 m

= 15 m³

Converting the volume of laboratory to liter;

since 1 m³ = 100 L; Then, we have:

15 × 1000 = 15,000 L

Using ideal gas equation to determine the moles of ethanol in vapor phase; we have:

PV = nRT

Making n the subject of the formula; we have:

$n = \frac{PV}{RT}$

$n = \frac{0.078 * 15000}{0.082*290}$

n = 47. 88 mol of ethanol

Moles of ethanol in 1.0 L bottle can be calculated as follows:

Since numbers of moles = $\frac{mass}{molar mass}$

and mass = density × vollume

Then; we can say ;

number of moles = $\frac{density*volume }{molar mass of ethanol}$

number of moles = $\frac{0.785g/cm^3*1000cm^3}{46.07g/mol}$

number of moles = $\frac{&85}{46.07}$

number of moles = 17.039 mol

Thus , all the ethanol present in the laboratory will evaporate since the mole of ethanol present in vapor is greater. The volume of ethanol left will therefore be zero.

5 0

3 years ago