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3 years ago

Why is oxygen written with a subscript 2 in CO2?

Chemistry

2 answers:

Alexeev081 [22]3 years ago

6 0

Answer:

Explanation:

the answer is b

Ronch [10]3 years ago

6 0

the answer is b because C+o2

c= carbon, o= oxygen

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two atoms respectively have Z=12, A=26 and Z=14, A=26. Can these two atoms be classified as isotopes of the same element?

aleksley [76]

No because they have the same number of protons not neutrons. fine, their mass nos are equal but isotopy is due to different number of neutrons.

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2 years ago

Sodium hydroxide reacts with aluminum and water to produce hydrogen gas: 2 Al(s) + 2 NaOH(aq) + 6 H2O(l) → 2 NaAl(OH)4(aq) + 3 H

lianna [129]

Answer:

The mass of hydrogen gas formed is 0.205 grams

Explanation:

Step 1: Data given

Mass of 1.83 grams of Al

Mass of NaOH = 4.30 grams

Molar mass of Al = 26.98 g/mol

Molar mass of NaOH = 40 g/mol

Step 2: The balanced equation:

2 Al(s) + 2 NaOH(aq) + 6 H2O(l) → 2 NaAl(OH)4(aq) + 3 H2(g)

Step 3: Calculate moles of Al

Moles Al = mass Al / Molar mass Al

Moles Al = 1.83 grams / 26.98 g/mol

Moles Al = 0.0678 moles

Step 4: Calculate moles of NaOH

Moles NaOH = 4.30 grams / 40 g/mol

Moles NaOH = 0.1075 moles

Step 5: Calculate limiting reactant

For 2 moles of Al, we need 2 moles of NaOH

Aluminium is the limiting reactant. It will completely be consumed ( 0.0678 moles)

NaOH is in excess. There will react 0.0678 moles

There will remain 0.1075 - 0.0678 = 0.0397 moles

Step 6: Calculate moles of hydrogen

For 2 moles of Al, we need 2 moles of NaOH, to produce 3 moles of hydrogen

For 0.0678 moles of Al, there is produced 0.0678 *3/2 = 0.1017 moles of H2

Step 7: Calculate mass of H2

Mass of H2 = Moles H2 * Molar mass of H2

Mass of H2 = 0.1017 moles * 2.02 g/mol

Mass of H2 = 0.205 grams

The mass of hydrogen gas formed is 0.205 grams

6 0

2 years ago

What's an element in period 5 with larger radius than Yttrium?

eimsori [14]

Rubidium or strontium have larger a larger atomic radius since the further left on the periodic table you go, the larger the sizes of the atoms are. This trend can be explained through effective nuclear charge which explains how the further left and down you go, the less the atoms nucleus is able to pull in the electrons around it.

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3 years ago

Two or more compounds that have the same molecular formula, but different arrangements of their atoms, are called_____ isomers.

dusya [7]

Structural isomers, as the structure of the molecule is different

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3 years ago

what is meant by a calibration curve for a colored substance being studied with a spectrophotometer? How is a calibration curve

BlackZzzverrR [31]

Answer:

The concentration of the analyte is determined by fitting the absorbance or transmittance obtained by spectrophotometric analysis of the unknown solution into the calibration curve.

Explanation:

In a calibration curve, the instrumental response (absorbance or transmittance), is plotted against the concentration of the analyte (the substance to be measured). The analyst is expected to prepare a series of standard solutions of the analyte within a range of solution concentrations close to the expected concentration of analyte in the unknown solution. The method of least squares may be used to determine the best fit of the line, thus, the concentration of the analyte. This method is only used for the determination of the concentration of coloured substances (spectrophotometry).

3 0

3 years ago