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3 years ago

Compare and contrast the fine and coarse adjustment knobs on a microscope

Chemistry

1 answer:

IceJOKER [234]3 years ago

8 0

The fine adjustment knob focuses an image. The coarse adjustment knod moves the slide up or down.

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Write a balanced equation for the complete combustion of propane gas, C3H8, with

Advocard [28]

Answer:

Explanation:

Balancing Carbon atoms on the right side,

Balancing Hydrogen atoms on the right side,

Balancing Oxygen atoms on the left side,

The reactants are on the left side of the reaction:

Propane and oxygen are the reactants.

The products are on the right side of the reaction:

Carbon dioxide and water are the products.

forgive me if im incorrect or leaving things out

8 0

2 years ago

A sample of neon gas in a bulb is at 149.05 °C and 349.84 kPa. If the pressure drops

KonstantinChe [14]

The new temperature (in °C) of the gas, given the data is –148.20 °C

<h3>Data obtained from the question </h3>

Initial temperature (T₁) = 149.05 °C = 149.05 + 273 = 422.05 K
Initial pressure (P₁) = 349.84 KPa
Volume = constant
New pressure (P₂) = 103.45 KPa
New temperature (T₂) =?

<h3>How to determine the new temperature </h3>

The new temperature of the gas can be obtained by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

Since the volume is constant, we have:

P₁ / T₁ = P₂ / T₂

349.84 / 422.05 = 103.45 / T₂

Cross multiply

349.84 × T₂ = 103.45 × 422.05

Divide both side by 349.84

T₂ = (103.45 × 422.05) / 349.84

T₂ = 124.80 K

Subtract 273 from 124.80 K to express in degree celsius

T₂ = 124.80 – 273

T₂ = –148.20 °C

Learn more about gas laws:

brainly.com/question/6844441

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6 0

2 years ago

A sample of As weighs 73.2 grams. Will a sample of Kr that contains the same number of atoms weigh more or less than 73.2 grams?

My name is Ann [436]

Answer:

This means a sample of 73.2 grams As atoms weighs less than the same amount of Kr atoms

Explanation:

Step 1: Data given

Mass of As = 73.2 grams

Molar mass As = 74.92 g/mol

Molar mass of Kr = 83.80 g/mol

Step 2: Calculate moles As

Moles As = Mass As / molar mass As

Moles As = 73.2 grams . 74.92 g/mol

Moles As = 0.977 moles

Step 3: Calculate As atoms

As atoms = moles As * number of Avogadro

As atoms = 0.977 moles * 6.02 * 10^23

As atoms = 5.88 *10^23 As atoms

Step 4: Calculate moles Kr

Moles Kr = Atoms Kr / number of Avogadro

Moles Kr = 5.88 * 10^23 Kr atoms / 6.02 *10^23

Moles Kr = 0.977 moles

Step 5: Calculate mass Kr

Mass Kr = moles Kr * molar mass Kr

Mass Kr = 0.977 moles * 83.80 g/mol

Mass Kr = 81.9 grams

This means a sample of 73.2 grams As atoms weighs less than the same amount of Kr atoms

8 0

3 years ago

Calculate the number of moles and the mass of the solute in each of the following solutions:

frosja888 [35]

Answer:

For a: The number of moles of KI are $2.7\times 10^{-5}$ and mass is $4.482\times 10^{-3}g$

For b: The number of moles of sulfuric acid are $1.65\times 10^{-5}$ and mass is $1.617\times 10^{-3}g$

For c: The number of moles of potassium chromate are $2.84\times 10^{-2}$ and mass is 5.51 g.

For d: The number of moles of ammonium sulfate are 39.018 moles and mass is 5155.84 grams.

Explanation:

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$ .....(1)

To calculate the number of moles of a substance, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(2)

For a:

Molarity of KI = $8.23\times 10^{-5}M$

Volume of solution = 325 mL = 0.325 L (Conversion factor: 1 L = 1000 mL)

Putting values in equation 1, we get:

$8.25\times 10^{-5}mol/L=\frac{\text{Moles of KI}}{0.325L}\\\\\text{Moles of KI}=2.7\times 10^{-5}mol$

Now, using equation 2, we get:

Moles of KI = $2.7\times 10^{-5}mol$

Molar mass of KI = 166 g/mol

Putting values in equation 2, we get:

$2.7\times 10^{-5}mol=\frac{\text{Mass of KI}}{166g/mol}\\\\\text{Mass of KI}=4.482\times 10^{-3}g$

Hence, the number of moles of KI are $2.7\times 10^{-5}$ and mass is $4.482\times 10^{-3}g$

For b:

Molarity of sulfuric acid = $22\times 10^{-5}M$

Volume of solution = 75 mL = 0.075 L

Putting values in equation 1, we get:

$22\times 10^{-5}mol/L=\frac{\text{Moles of sulfuric acid}}{0.075L}\\\\\text{Moles of }H_2SO_4=1.65\times 10^{-5}mol$

Now, using equation 2, we get:

Moles of sulfuric acid = $1.65\times 10^{-5}mol$

Molar mass of sulfuric acid = 98 g/mol

Putting values in equation 2, we get:

$1.65\times 10^{-5}mol=\frac{\text{Mass of }H_2SO_4}{98g/mol}\\\\\text{Mass of }H_2SO_4=1.617\times 10^{-3}g$

Hence, the number of moles of sulfuric acid are $1.65\times 10^{-5}$ and mass is $1.617\times 10^{-3}g$

For c:

Molarity of potassium chromate = $0.1135M$

Volume of solution = 0.250 L

Putting values in equation 1, we get:

$0.1135mol/L=\frac{\text{Moles of }K_2CrO_4}{0.250L}\\\\\text{Moles of }K_2CrO_4=2.84\times 10^{-2}mol$

Now, using equation 2, we get:

Moles of potassium chromate = $2.84\times 10^{-2}mol$

Molar mass of potassium chromate = 194.2 g/mol

Putting values in equation 2, we get:

$2.84\times 10^{-2}mol=\frac{\text{Mass of }K_2CrO_4}{194.2g/mol}\\\\\text{Mass of }K_2CrO_4=5.51g$

Hence, the number of moles of potassium chromate are $2.84\times 10^{-2}$ and mass is 5.51 g.

For d:

Molarity of ammonium sulfate = 3.716 M

Volume of solution = 10.5 L

Putting values in equation 1, we get:

$3.716mol/L=\frac{\text{Moles of }(NH_4)_2SO_4}{10.5L}\\\\\text{Moles of }(NH_4)_2SO_4=39.018mol$

Now, using equation 2, we get:

Moles of ammonium sulfate = 39.018 mol

Molar mass of ammonium sulfate = 132.14 g/mol

Putting values in equation 2, we get:

$39.018mol=\frac{\text{Mass of }(NH_4)_2SO_4}{132.14g/mol}\\\\\text{Mass of }(NH_4)_2SO_4=5155.84g$

Hence, the number of moles of ammonium sulfate are 39.018 moles and mass is 5155.84 grams.

3 0

4 years ago

The electronic configuration of an element is given below.

Shalnov [3]

Answer:

It is reactive because it has to gain an electron to have a full outermost energy level.

Explanation:

The electron configuration of oxygen is 1s2,2s2 2p4.

Oxygen is in group six in the periodic table so it has six electrons in its valence shell. This means that it needs to gain two electrons to obey the octet rule and have a full outer shell of electrons (eight).

3 0

2 years ago