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3 years ago

Compare and contrast lithium and potassium and also fluorine !!!??? Pls need help

1 answer:

8 0

lithium and potassium are both in the alkali family and they are metals. Fluorine is a non-metal and lives in the halogens family. But, each of them have 2 valence electrons in the innermost ring

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Ben Tooclose is being chased through the woods by a bull moose which he attempting to photograph.the enormous mass of the bull m

Elodia [21]

Newton's first law of motion is the law of inertia. There are basically "two parts" to the law of inertia. The first part says that an object at rest tends to remain at rest unless it is acted on by an outside force. Think of gravity.
-Hope that helps!! :)

4 0

4 years ago

The enthalpy change of reaction is also called

Vikentia [17]

C) Heat of the reaction.

7 0

3 years ago

Read 2 more answers

What is the mass of an object if the density is 7.85g/l and the volume is 41.25ml

Blababa [14]

The density is the ratio between mass and volume. So the mass is the product between density and volume. But! You have to control the units of measure.

7.85 g/l = 0.00785 kg/l

41.25 ml = 0.04125 l

Mass = (0.00785) x (0.04125) = 0,00032381 kg ---> 0,32381 g

(I hope this is right )

7 0

3 years ago

Methanol, ethanol, and n−propanol are three common alcohols. When 1.00 g of each of these alcohols is burned in air, heat is lib

KengaRu [80]

Answer:

For methanol: Heat of combustion = -22.6 kJ / 0.0312 moles = -724.3590 kJ/mol (negative sign signifies release of heat)

For ethanol: Heat of combustion = -29.7 kJ / 0.0217 moles = -1368.6636 kJ/mol (negative sign signifies release of heat)

For propanol: Heat of combustion = -33.4 kJ / 0.0166 moles = -2012.0482 kJ/mol (negative sign signifies release of heat)

Explanation:

Given:

Mass of Methanol = 1.0 g

Mass of ethanol = 1.00 g

Mass of n-propanol = 1.00 g

For methanol:

2 CH₃OH + 3 O₂ ----> 2 CO₂ + 4 H₂O, ∆H₀ = -22.6 kJ/g (negative sign signifies release of heat)

1 g of methanol on combustion gives 22.6 kJ of energy

Calculation of moles of methanol:

$moles=\frac{Mass(m)}{Molar\ mass (M)}$

Molar mass of methanol = 32.04 g/mol

Thus moles of methanol = 1 g/ (32.04 g/mol) = 0.0312 moles

Hence energy in kJ/mol:

Heat of combustion = -22.6 kJ / 0.0312 moles = -724.3590 kJ/mol (negative sign signifies release of heat)

For ethanol:

C₂H₅OH + 3 O₂ ----> 2 CO₂ + 3 H₂O, ∆H₀ = -29.7 kJ/g (negative sign signifies release of heat)

1 g of ethanol on combustion gives 29.7 kJ of energy

Calculation of moles of ethanol:

$moles=\frac{Mass(m)}{Molar\ mass (M)}$

Molar mass of ethanol = 46.07 g/mol

Thus moles of ethanol = 1 g/ (46.07 g/mol) = 0.0217 moles

Hence energy in kJ/mol:

Heat of combustion = -29.7 kJ / 0.0217 moles = -1368.6636 kJ/mol (negative sign signifies release of heat)

For propanol:

2 C₃H₇OH + 9 O₂ ----> 6 CO₂ + 8 H₂O, ∆H₀ = -33.4 kJ/g , (negative sign signifies release of heat)

1 g of methanol on combustion gives 33.4 kJ of energy

Calculation of moles of methanol:

$moles=\frac{Mass(m)}{Molar\ mass (M)}$

Molar mass of methanol = 60.09 g/mol

Thus moles of methanol = 1 g/ (60.09 g/mol) = 0.0166 moles

Hence energy in kJ/mol:

Heat of combustion = -33.4 kJ / 0.0166 moles = -2012.0482 kJ/mol (negative sign signifies release of heat)

5 0

3 years ago

What causes water to change state? Select the most correct answer.

Tems11 [23]

Answer:

D. Water changes state when it loses or gains energy.

Explanation:

When water gains energy, it turns from ice to water, or water to gas. When water loses energy, it turns from gas to water, or water to ice.

Particles in the water move faster and create more energy when heated, and this causes them to spread wider apart and change. Particles slow down and move closer together when they get cold.

5 0

3 years ago