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3 years ago

Match the vocabulary terms to their definitions.

Chemistry

2 answers:

vesna_86 [32]3 years ago

7 0

Answer:

1. The standard metric unit of length is a meter.

2. A proposed explanation for a scientific problem is a hypothesis.

3. The standard unit of volume is a liter.

4. The curved top surface of a liquid column is the meniscus.

5. A quantity in an experiment that remains unchanges or constant is a controlled variable (control)

6. The amount of matter in an object is mass.

Dennis_Churaev [7]3 years ago

6 0

Explanation:

1. Standard metric unit of length → meter

Unit is defined as the quantity that is used as a standard for measurement. Meter, Centimeters, hectometers are the units which is used to express length of a substance.

2. A proposed explanation for a scientific problem → hypothesis

Hypothesis is defined as explanation or supposition made on the basis of limited evidence for a specific process or phenomena.

3. Standard unit of volume → liter

Liter is the unit which is used to express volume occupied by the substance.

4. The curved top surface of a liquid column → meniscus

Liquids from two types of meniscus :

Concave shaped curve due to adhesive forces and is dominating inside the glass.

Convex shaped curve due to due to cohesive forces and is dominating on the top of glass.

5. A quantity in an experiment that remains unchanged or constant → control

Control variable is an experimental variable which is kept unchanged or remains constant through out the course of an experiment.

6. Amount of matter in an object → mass

Mass of the body is defined as quantity of present in a given object. It is a constant quantity.

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Answer: 1.6L

Explanation:

V1 = 1.50 L,

V2 =?

n1 = 3mol

n2 = 3 + 0.2 = 3.2mol

From PV = nRT

V1 /n1 = V2/n2

1.5/3 = V2 /3.2

V2 = (1.5/3/) x 3.2 = 1.6L

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3 years ago

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3 years ago

extremely hot.When a student went to open the car doo , he burned his finger. What two forms of energy were responsible for the

charle [14.2K]

Answer:

radiation and conduction

Explanation:

During a warm summer day, a car became extremely hot. When a student went to open the car door, he burned his fingers. What two forms of energy were responsible for the student burning his fingers?

Solution:

Heat is the transfer of energy from a warmer object to a cooler object. For heat transfer to occur, there have to be a difference in temperature between two objects.

Heat can be transferred in three ways: by conduction, by convection, and by radiation.

Conduction is the transfer of thermal energy between bodies through direct contact. Convection is the transfer of thermal energy through the movement of heat in a liquid or gas. Radiation is the transfer of thermal energy through thermal emission by electromagnetic waves.

During a warm summer day, The sun makes the car to become hot through energy transfer from the sun to the car. When the student touch the car, there is heat transfer as a result of conduction.

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3 years ago

For the solution resulting from dissolved 0.32 g of naphthalene (C10H8) in 25 g of benzene (C6H6) at temperature of 26.1°C, calc

grandymaker [24]

Answer:

See explanation

Explanation:

Number of moles of naphthalene = 0.32g/128.1705 g/mol = 0.0025 moles

Molality = number of moles/ mass of Solvent in kilograms

Molality = 0.0025/0.025 Kg

Morality = 0.1 m

But

∆T= K × i × m

Where ∆T = boiling point elevation

i= number of particles (this is equal to 1 because naphthalene is molecular and not ionic)

m= molality of naphthalene = 0.1 m

K= boiling point elevation constant = 5.12 °C/m

∆T= 5.12 °C/m ×0.1 = 0.512°C

For freezing point depression

∆T= K× i × m

Where ∆T= freezing point depression

i= number of particles (this is equal to 1 because naphthalene is molecular and not ionic)

m= molality of naphthalene = 0.1 m

K= freezing point depression constant = 2.67 °C/m

∆T= 2.67 °C/m ×0.1 = 0.267°C

From Raoult's law;

∆P = XBPA°

Where;

∆P = vapour pressure lowering

XB = mole fraction of solute

PA° = vapour pressure of pure solvent

Number of moles of solvent = mass/molar mass = 25g/ 78 g/mol= 0.3205 moles

Total number of moles = number of moles of solute + number of moles of solvent = 0.0025 moles + 0.3205 moles = 0.323 moles

Mole fraction of solute = 0.0025 moles/0.323 moles = 0.0077

Vapour pressure of benzene = 100 torr

Therefore;

∆P = 0.0077 × 100torr = 0.77 torr

Hence;

∆P = 0.77 torr

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Here, for the given chemical formula, the subscript of N is 1 and the subscript present outside is 2. So, 1 x 2 = 2 and for oxygen, 3 x 2 = 6

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