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3 years ago

Who can help me please ? Yes I will give BRAINLIST . And yes this is 6th grade work . Please help me ( it’s science btw )

Chemistry

2 answers:

lana [24]3 years ago

6 0

Answer:

true and b are the answers I think

IrinaVladis [17]3 years ago

4 0

Answer:

true/precipitation

Explanation:

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21-B. Mn was used as an internal standard for measuring Fe by atomic absorption. A standard mixture containing 2.00 mg Mn/mL and

Korvikt [17]

Answer:

0.0693M Fe

Explanation:

It is possible to quantify Fe in a sample using Mn as internal standard using response factor formula:

F = A(analyte)×C(std) / A(std)×C(analyte) (1)

Where A is area of analyte and std, and C is concentration.

Replacing with first values:

F = 1.05×2.00mg/mL / 1.00×2.50mg/mL

F = 0.84

In the unknown solution, concentration of Mn is:

13.5mg/mL × (1.00mL/6.00mL) = 2.25 mg Mn/mL

Replacing in (1) with absorbances values and F value:

0.84 = 0.185×2.25mg/mL / 0.128×C(analyte)

C(analyte) = 3.87 mg Fe / mL

As molarity is moles of solute (Fe) per liter of solution:

$\frac{3.87 mg Fe}{mL} \frac{1g}{1000mg} \frac{1mol}{55.845g} \frac{1000mL}{1L}$ = 0.0693M Fe

7 0

3 years ago

Read 2 more answers

Sita made a model of three parts of the solar system, the Sun, Earth and Moon.

Bumek [7]

She must have used the torch as Sun, the tennis ball as Earth and the marble as Moon.

8 0

2 years ago

Give the number of significant figures in this number: 7.8 x 10¹²

denis-greek [22]

The number is written in scientific notation.

The significant figures are the numbers known precisely plus 1 digit that is uncertain.

When the numbers are expressed in scientific notation all the digits before 10^n are significant.

So, 7 and 8 are significant figures and the answer is that the number of significant figures is 2.

Answer: 2

8 0

3 years ago

Please Help! Let P and V represent the pressure and volume of Xe(g). If a piston is used to reduce the volume of the gas to V/2

Elza [17]

1) 2P

2) Average speed does not change

Explanation:

To solve the first part of the problem, we can use Boyle's Law, which states that:

"For a fixed mass of an ideal gas kept at constant temperature, the pressure of the gas is inversely proportional to its volume"

Mathematically:

$pV=const.$

where

p is the pressure of the gas

V is its volume

For the Xe gas in this problem we can write

$p_1 V_1 = p_2 V_2$

where:

$p_1 = P$ is the initial pressure

$V_1=V$ is the initial volume

$V_2=\frac{V}{2}$ is the final volume

Solving for p2, we find the final pressure:

$p_2=\frac{P V_1}{V_2}=\frac{pV}{V/2}=2P$

So, the pressure has doubled.

The average speed of the atoms/molecules in the gas is given by the formula

$v_{rms}=\sqrt{\frac{3RT}{M}}$

where

R is the gas constant

T is the absolute temperature (in Kelvin) of the gas

M is the molar mass of the gas

$v_{rms}$ is known as rms speed of the particles in the gas

From the formula, we see that the speed of the atoms in the gas depends only on the temperature of the gas.

In the Xe(g) gas in this problem, the temperature is kept constant; therefore, since nothing changes in the formula, this means that the average speed also does not change.

8 0

3 years ago

Texas ranks __________ among the states in the amount of hazardous waste generated, carbon dioxide emissions, and toxic chemical

Tcecarenko [31]

Texas racked the first spot in the ranking of states that is characterized as the state with the most amount of waste generated, carbon dioxide emissions, generally environmentally toxic wastes being emitted to the atmosphere. This is caused by numerous human activities as well as the chemical plants present in the state.

6 0

3 years ago