Which of the samples shown represents an element?

What is the molarity of a solution if 300.0 ml of it contains 16.8 g of kno3? [formula weight: kno3, 101.11 amu]?

AVprozaik [17]

The molarity is count by dividing the mole of the solute within 1 liter of solvent. In this case, the KNO3 is 16.8g with 101.11 g/mol molar mass. Then we need to find the mol first. The calculation would be: 16.8g / (101.11g/mol)= 0.0166 mol.

Then the molarity would be: 0.0166mol/ 0.3l= 0.0498= 0.0553 M

6 0

3 years ago

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A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what woul

gayaneshka [121]

Answer:

10°C

Explanation:

Heat gain by water = Heat lost by the slice of pizza

Thus,

$m_{water}\times C_{water}\times \Delta T=Q$

<u>For water: </u>

Volume = 50.0 L

Density of water= 1 kg/L

So, mass of the water:

$Mass\ of\ water=Density \times {Volume\ of\ water}$

$Mass\ of\ water=1 kg/L \times {50.0\ L}$

Mass of water = 50 kg

Specific heat of water = 1 kcal/kg°C

ΔT = ?

For slice of pizza:

Q = 500 kcal

So,

$50\times 1\times \Delta T=500$

ΔT = 10°C

Increase in temperature = 10°C

3 0

2 years ago

According to the combined gas law, the pressure exerted by a gas is:

sergij07 [2.7K]

Answer : The correct option is, (d) inversely proportional to volume and directly proportional to the kelvin temperature

Explanation :

Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

$P\propto \frac{1}{V}$

Charles' Law : It is defined as the volume of the gas is directly proportional to the temperature of the gas at constant pressure and number of moles.

$V\propto T$

Gay-Lussac's Law : It is defined as the pressure of the gas is directly proportional to the temperature of the gas at constant volume and number of moles.

$P\propto T$

Combined gas law : It is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

$\frac{PV}{T}=K$

or,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

From the above information we conclude that the pressure exerted by a gas is inversely proportional to volume and directly proportional to the kelvin temperature.

Hence, the correct option is, (d)

3 0

2 years ago

Which is not a step in most scientific investigations?

Semenov [28]

1. is not a step in most scientific investigations.

4 0

3 years ago

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What is the current in the 30 ohm heating coil of a coffee maker that operates on a 120 volt circuit?

SpyIntel [72]

Answer:

4Amps. i can't see other questions clearly

Explanation:

$using ohms law \\ v = ir$

V=120 volt
R=30ohms
I=?

I=V/R

I=120/30

I=4amps

8 0

3 years ago