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lions [1.4K]
2 years ago
7

What kind of chemical reaction occurs in a hand-warming product that is worn inside gloves? Explain your answer.

Chemistry
1 answer:
ch4aika [34]2 years ago
5 0

Answer:

exothermic

Explanation:

Disposable hand warmers turn up the heat in your mittens by means of an exothermic reaction that, in essence, just creates rust.

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Complite the following reactions. NaOH(aq)+FeBr3(aq)→
stira [4]

Answer:

3NaOH+FeBr3>3NaBr+

Fe(OH)3

Explanation:

After writing the equation it has to be balanced

8 0
3 years ago
How many moles of sodium carbonate are contained by 57.3g of sodium carbonate
Lady_Fox [76]

Answer:

\boxed {\boxed {\sf 0.541 \  mol \ Na_2CO_3}}

Explanation:

We are asked to find how many moles of sodium carbonate are in 57.3 grams of the substance.

Carbonate is CO₃ and has an oxidation number of -2. Sodium is Na and has an oxidation number of +1. There must be 2 moles of sodium so the charge of the sodium balances the charge of the carbonate. The formula is Na₂CO₃.

We will convert grams to moles using the molar mass or the mass of 1 mole of a substance. They are found on the Periodic Table as the atomic masses, but the units are grams per mole instead of atomic mass units. Look up the molar masses of the individual elements.

  • Na:  22.9897693 g/mol
  • C: 12.011 g/mol
  • O: 15.999 g/mol

Remember the formula contains subscripts. There are multiple moles of some elements in 1 mole of the compound. We multiply the element's molar mass by the subscript after it, then add everything together.

  • Na₂ = 22.9897693 * 2= 45.9795386 g/mol
  • O₃ = 15.999 * 3= 47.997 g/mol
  • Na₂CO₃= 45.9795386 + 12.011 + 47.997 =105.9875386 g/mol

We will convert using dimensional analysis. Set up a ratio using the molar mass.

\frac {105.9875386  \ g \ Na_2CO_3}{1 \ mol \ Na_2CO_3}

We are converting 57.3 grams to moles, so we multiply by this value.

57.3 \ g \ Na_2CO_3} *\frac {105.9875386  \ g \ Na_2CO_3}{1 \ mol \ Na_2CO_3}

Flip the ratio so the units of grams of sodium carbonate cancel.

57.3 \ g \ Na_2CO_3} *\frac {1 \ mol \ Na_2CO_3}{105.9875386  \ g \ Na_2CO_3}

57.3 } *\frac {1 \ mol \ Na_2CO_3}{105.9875386 }

\frac {57.3 }{105.9875386 } \ mol \ Na_2CO_3

0.5406295944 \ mol \ Na_2CO_3

The original measurement of moles has 3 significant figures, so our answer must have the same. For the number we found that is the thousandth place. The 6 in the ten-thousandth place to the right tells us to round the 0 up to a 1.

0.541 \  mol \ Na_2CO_3

There are approximately <u>0.541 moles of sodium carbonate</u> in 57.3 grams.

6 0
2 years ago
A weight of 22.25g was obtained when 10-mL of water at 27C was pipet to empty Erlenmeyer flask. What is the volume delivered by
Nimfa-mama [501]

Answer:

the volume delivered by the pipette = 22.32 mL

Explanation:

To calculate this, let us first note that the density of water relates it weight and its volume (density = mass ÷ volume), hence we are going to use density to determine the volume.

Density of water = mass/volume = 0.997 g/ mL

mass = 22.25g

Density = 0.997g/mL

volume = ?

density = \frac{mass}{volume}\\\therefore volume = \frac{mass}{density}\\volume = \frac{22.25}{0.997}\\volume =  22.32\ mL

∴ the volume delivered by the pipette = 22.32 mL

<em>Please note that this calculation is based on the fact that the weight of the empty flask has been determined and canceled out.</em>

4 0
3 years ago
Which contains the greatest mass of oxygen: 0.75 mol of ethanol (C2H5OH), 0.60 mol of formic acid (HCO2H), or 1.0 mol of water (
alisha [4.7K]

Answer: formic acid (HCOOH) contains the greatest mass of oxygen

Explanation:Please see attachment for explanation

3 0
3 years ago
The concentration of gallium in silicon is 5.0 × 10−7 at%. What is the concentration in kilograms of gallium per cubic meter?
Step2247 [10]

Answer:

[ Ga ] = 1.163 E-8 Kg/m³

Explanation:

  • %wt = [(mass Ga)/(mass Si)]*100 = 5.0 E-7 %

⇒ 5.0 E-9 = m Ga/m Si

assuming: m Si = 100 g = 0.1 Kg

⇒ m Ga = (5.0 E-9)*(0.1 Kg) = 5 E-10 Kg

∴ density (δ) Si = 2.33 Kg/m³

⇒ Volume Si = (0.1 Kg)*(m³/2.33 Kg) = 0.043 m³

⇒ [ Ga ] = (5 E-10 Kg)/(0.043 m³) = 1.163 E-8 Kg/m³

⇒ [ Ga ] =

3 0
3 years ago
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