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1 year ago

A filament of a light bulb is made from a pure sample of tungsten.

Chemistry

1 answer:

GenaCL600 [577]1 year ago

8 0

Answer:

The correct options are:

1) Pure chemical substance

2) Element.

Explanation:

each of the term is explained below:

1) Mixture: Since tungsten is an element in periodic table thus it is not a mixture.

2) False by definition of mixture.

3) false by definition of mixture.

4) Solution: Tungsten in a filament is in solid form hence solution is incorrect.

5) Since it is given in the question itself that the sample is pure hence option 'E' is correct as chemical substance is a pure substance that has a homogeneous composition and the sample in the question is given as pure.

6) Compound: By definition of compound it is formed by mixing 2 or more elements but since tungsten is an element that occurs independently in nature hence it is not a compound.

7) Tungsten is a element in the periodic table with atomic number 74.

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How many moles of oxygen atoms are in 132.2 g of MgSO4?

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4.4moles of oxygen atoms

Explanation:

Given parameters:

Mass of MgSO₄ = 132.2g

Unknown:

Number of moles of oxygen atoms = ?

Solution:

The number of moles is the quantity of substance that contains the avogadro's number of particles.

To solve for this;

Number of moles = $\frac{mass}{molar mass}$

Molar mass of MgSO₄ = 24 + 32 + 4(16) = 120g/mole

Number of moles = $\frac{132.2}{120}$ = 1.1 moles

1 moles of MgSO₄ we have 4 moles of oxygen atoms

1.1 moles of MgSO₄ contains 4 x 1.1 moles = 4.4moles of oxygen atoms

learn more:

number of moles brainly.com/question/1841136

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2 years ago

One reactant with a mass of 10 grams is combined with another reactant with a mass of 8 grams in a sealed container. After the r

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18g is the most reasonable mass after the reaction

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2 years ago

Some building materials contain small capsules filled with paraffin wax to improve the insulating properties of the materials. T

alisha [4.7K]

Answer:

(a)

From surrounding to wax

(b)

Q = 2.62 KJ

(c)

Density of a substance is defined as the no. of particles of the substance, that occur in a unit volume. So, when the substance melts, the inter-molecular attractive forces and bonds between molecules or atoms are weakened. This, increases the distance between the molecules or atoms. Hence, the no. of particles in a unit volume is decreased. As, a result of this, the density of the substance also decreases.

Explanation:

(a)

During the melting process, the solid material or substance requires energy, in order to break the bonds between its molecules or atoms.

Therefore, while the wax is melting, the net flow of thermal energy is from surrounding to the wax.

(b)

The amount of energy required to melt solid paraffin wax is given by the formula:

Q = nC

where,

Q = amount of energy

C = Molar Heat of Fusion = 48.78 KJ/mol

n = No. of Moles = Mass in gram/Molar Mass = (15.2 g)/(282.62 g/mol)

n = 0.0538 mol

Therefore,

Q = (0.0538 mol)(48.78 KJ/mol)

Q = 2.62 KJ

(c)

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2 years ago

COCl2(g) decomposes according to the equation above. When pure COCl2(g) is injected into a rigid, previously evacuated flask at

mestny [16]

Answer: The value of $K_p$ for the reaction at 690 K is 0.05

Explanation:

We are given:

Initial pressure of $COCl_2$ = 1.0 atm

Total pressure at equilibrium = 1.2 atm

The chemical equation for the decomposition of phosgene follows:

$COCl_2(g)\rightleftharpoons CO(g)+Cl_2(g)$

Initial: 1 - -

At eqllm: 1-x x x

We are given:

Total pressure at equilibrium = [(1 - x) + x+ x]

So, the equation becomes:

$[(1 - x) + x+ x]=1.2\\\\x=0.2atm$

The expression for $K_p$ for above equation follows:

$K_p=\frac{p_{CO}\times p_{Cl_2}}{p_{COCl_2}}$

$p_{CO}=0.2atm\\p_{Cl_2}=0.2atm\\p_{COCl_2}=(1-0.2)=0.8atm$

Putting values in above equation, we get:

$K_p=\frac{0.2\times 0.2}{0.8}\\\\K_p=0.05$

Hence, the value of $K_p$ for the reaction at 690 K is 0.05

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1 year ago

You evaporate all of the water from 100 mL of NaCl solution and obtain 11.3 grams of NaCl. What was the molarity of the NaCl sol

kicyunya [14]

Answer:

Molarity = 1.93 mol.L⁻¹

Explanation:

Molarity is the unit of concentration used to specify the amount of solute in given amount of solution. It is expressed as,

Molarity = Moles / Volume of Solution ----- (1)

Data Given;

Mass = 11.3 g

Volume = 100 mL = 0.10 L

First calculate Moles for given mass as,

Moles = Mass / M.mass

Moles = 11.3 g / 58.44 g.mol⁻¹

Moles = 0.1933 mol

Now, putting value of Moles and Volume in eq. 1,

Molarity = 0.1933 mol ÷ 0.10 L

Molarity = 1.93 mol.L⁻¹

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2 years ago