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3 years ago

Energy to thermal energy.

Chemistry

1 answer:

sergiy2304 [10]3 years ago

3 0

A hair dryer converts "electrical energy" to "thermal energy".

Option: C

<u>Explanation</u>:

The "electricity" is converted to "heat energy" in a "wire coil". Here electricity process "air" out of "the hair dryer" with the help of forced convection. Most hairdryers use a nichrome wire coil that will not oxidize when heated and allowing it to "blow" the hair dry with high temperature air which speeds up evaporation. Thus "wire heats" the "air faster", in most of the "hair dryers" the "air" is only in "the barrel" for "half of a second".

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An unknown noble gas has a density of 5.84 g dm-3 at STP. Calculate its molar mass, and so identify the gas.

bagirrra123 [75]

The noble gas is Xenon and its molar mass is 131 g/mol.

<h3>What is the molar mass of the noble gas?</h3>

The molar mass of the noble gas is determined as follows;

Let molar mass of unknown gas be M, and mass of gas be m

Density of the noble gas, ρ = 5.8 g/dm³

density = m/V

At STP;

temperature, T = 273.15 K
pressure, P = 1 atm
molar gas constant, R = 0.0821 L.atmK⁻¹mol⁻¹

From ideal gas equation:

PV = nRT

where n = m/M

PV = mRT/M

M = mRT/PV

M = 0.0821 * 273.15 * 5.84/1

Molar mass of the noble gas = 131 g/mol

The noble gas is Xenon which has molar mass approximately equal to 131 g/mol.

Learn more about molar mass at: brainly.com/question/837939

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6 0

1 year ago

Lead forms two compounds with oxygen. One contains 2.98g of lead and 0.461g of oxygen. The other contains 9.89g of lead and 0.76

aliina [53]

The given question is incomplete, the complete question is:

Lead forms two compounds with oxygen. One contains 2.98g of lead and 0.461g of oxygen. The other contains 9.89g of lead and 0.763g of oxygen. For a given mass of oxygen, what is the lowest whole-number mass ratio of lead in the two compounds that combines with a given mass of oxygen?

Answer:

The lowest whole-number mass ratio in the two compounds is 1:2.

Explanation:

There is a need to find the mole ratio between lead and oxygen atoms in order to find the whole-number mass ratio of lead in the two compounds. In the first compound, the given mass of lead is 2.98 grams, the molar mass of lead is 207.2 gram per mole.

The no. of moles can be determined by using the formula,

moles = mass/molecular mass

moles = 2.98 g/207.2 g/mol

= 0.0144 moles

The mass of oxygen in the compound I is 0.461 grams, the molecular mass of oxygen is 16 gram per mol.

moles = 0.461 g /16 g/mol

= 0.0288 moles

The ratio between the lead and oxygen in the compound I is 0.0144/0.0288 = 1:2

On the other hand, in the compound II, the mass of lead given is 9.89 grams, therefore, the moles of lead in compound II is,

moles = 9.89 g / 207.2 g/mol

= 0.0477 moles

The mass of oxygen given in compound II is 0.763 grams, the moles of oxygen present in the compound II is,

moles = 0.763 g / 16 g

= 0.0477 moles

The ratio between the lead and oxygen in the compound II is, 0.0477 moles lead /0.0477 moles oxygen = 1:1

Hence, of the two compounds, the lowest ratio is found in the compound I, that is, 1:2.

4 0

3 years ago

One gallon of water has a mass of 3.78kg. Water is 11.2% hydrogen by mass. Calculate the mass of hydrogen contained in this gall

olchik [2.2K]

Answer:

A model is developed for predicting oxygen uptake, muscle blood flow, and blood chemistry changes under exercise conditions. In this model, the working muscle mass system is analyzed. The conservation of matter principle is applied to the oxygen in a unit mass of working muscle under transient exercise conditions. This principle is used to relate the inflow of oxygen carried with the blood to the outflow carried with blood, the rate of change of oxygen stored in the muscle myoglobin, and the uptake by the muscle. Standard blood chemistry relations are incorporated to evaluate venous levels of oxygen, pH, and carbon dioxide.

Explanation:

8 0

3 years ago

Why is calcium chloride (rock salt, CaCl2) more effective than sodium chloride (table salt, NaCl) at de-icing roads in the winte

Tema [17]

Answer:

The correct option is;

D. Calcium chloride breaks into 3 ions, while sodium chloride only breaks into 2 ions

Explanation:

To help melt the ice on icy streets, calcium chloride (CaCl₂) is a more preferred salt type to sodium chloride (NaCl) as when it dissociates into ions in the ice, it forms three ions: a calcium ion, Ca²⁺, and two chloride ions, 2 Cl⁻, while sodium chloride forms two ions: one sodium ion, Na⁺, and one chloride ion, Cl⁻

According to the freezing point depression equation, we have;

ΔT = $K_f$ × m × i