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3 years ago

URGENT HELP PLEASE what is an isotope? And how do you calculate isotopes

1 answer:

4 0

Isotopes are atoms of the same element with the same number of protons but different number of neutrons. you calculate them by multiplying the abundance of the isotope by its relative atomic mass and then adding them up

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What are the limitations of litmus paper and phenolphthalein indicators? Name two other indicators that can be used that do not

ra1l [238]

False reading may be obtained if there is a run over from adjacent reagent area in excessively wetted strips

Phenolphthalein only works efficiently from 4 to 10 ph

Litmus and phenolphthalein and methyl orange indicators can only allow you to tell if solution is alkaline,neutral or acidic

The two indicators with less limitations are methyl orange and thymol blue

7 0

3 years ago

Read 2 more answers

The bottom number on each element on the Periodic Table is called

Flura [38]

Answer:

The bottom number on each element of the periodic table are called the 4f series or lanthanoids and 5f or actanoids. They are also called inner transition elements.

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2 years ago

Control activities are performed within processes (e.g., segregation of duties required in processing cash receipt transactions)

galina1969 [7]

Answer:

a. True

Explanation:

The control objectives seek to support the fulfillment of the critical factors of business success, in order to finally support the achievement of the institutional objectives, on this the CITI is based

It is very important to clearly identify the relationships of the control objectives with other internal control elements such as:

· Critical success factors receive direct support from control objectives to support compliance.

· The control objectives are made up of control goals, which allow them to have a more detailed perspective of the control objectives and at the same time facilitate the evaluation of their compliance.

CITI CONCEPT:

It is the set of administration elements that a company establishes in a coordinated way so that the use of information technology resources effectively supports the institutional objectives of the company

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3 years ago

Hydrogen gas (a potential future fuel) can be formed by the reaction of methane with water according to the following equation:

rusak2 [61]

Answer:

60.42% is the percent yield of the reaction.

Explanation:

Moles of methane gas at 734 Torr and a temperature of 25 °C.

Volume of methane gas = V = 26.0 L

Pressure of the methane gas = P = 734 Torr = 0.9542 atm

Temperature of the methane gas = T = 25 °C = 298.15 K

Moles of methane gas = n

$PV=nRT$

$n=\frac{PV}{RT}=\frac{0.9542 atm\times 26.0L}{0.0821 atm L/mol K\times 298.15 K}=1.0135 mol$

Moles of water vapors at 700 Torr and a temperature of 125 °C.

Volume of water vapor = V' = 23.0 L

Pressure of water vapor = P' = 700 Torr = 0.9100 atm

Temperature of water vapor = T' = 125 °C = 398.15 K

Moles of water vapor gas = n'

$P'V'=n'RT'$

$n'=\frac{PV}{RT}=\frac{0.9100 atm\times 23.0L}{0.0821 atm L/mol K\times 398.15 K}=0.6402 mol$

$CH_4(g)+H_2O(g)\rightarrow CO(g)+3H_2(g)$

According to reaction , 1 mol of methane reacts with 1 mol of water vapor. As we can see that moles of water vapors are in lessor amount which means it is a limiting reagent and formation of hydrogen gas will depend upon moles of water vapors.

According to reaction 1 mol of water vapor gives 3 moles of hydrogen gas.

Then 0.6402 moles of water vapor will give:

$\frac{3}{1}\times 0.6402 mol=1.9208 mol$ of hydrogen gas