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Mekhanik [1.2K]
2 years ago
10

Pls give me the right answer

Chemistry
1 answer:
Alchen [17]2 years ago
5 0
The answer to the question is D
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A laboratory technician combined sodium hydroxide with excess iron(II) nitrate. A reaction took place according to this chemical
Whitepunk [10]

 The initial  mass  of sodium hydroxide  is  3.3 g (answer C)

 <u><em>calculation</em></u>

Step 1 : find the  moles of iron (ii) hydroxide (  Fe(OH)₂

moles =  mass÷  molar mass

from periodic table the  molar mass of Fe(OH)₂  = 56 + [16 +1]2  = 90 g/mol

moles  is therefore = 3.70 g÷ 90 g/mol = 0.041 moles

Step 2:  use the mole ratio to  calculate the moles of  sodium hydroxide (NaOH)

   from given equation  NaOH : Fe(OH)₂    is 2 :1

therefore the moles of NaOH = 0.041 x 2 = 0.082 moles

Step 3: find  mass of NaOH

mass = moles x molar mass

from the periodic table the  molar mass of NaOH = 23 +16 +1  = 40 g/mol

mass  = 0.082  moles x 40 g/mol = 3.3 g ( answer C)


8 0
3 years ago
How many particles are there in 1 mole of hand sanitizer?.
andre [41]

Answer: 6.02214 × 1023 particles

Explanation: did math

4 0
2 years ago
Determine total H for bonds broken and formed, the overall change in H, and the final answer with units. Is it ENDOthermic or EX
Mrac [35]
  • E(Bonds broken) = 1371 kJ/mol reaction
  • E(Bonds formed) = 1852 kJ/mol reaction
  • ΔH = -481 kJ/mol.
  • The reaction is exothermic.
<h3>Explanation</h3>

2 H-H + O=O → 2 H-O-H

There are two moles of H-H bonds and one mole of O=O bonds in one mole of reactants. All of them will break in the reaction. That will absorb

  • E(Bonds broken) = 2 × 436 + 499 = 1371 kJ/mol reaction.
  • ΔH(Breaking bonds) = +1371 kJ/mol

Each mole of the reaction will form two moles of water molecules. Each mole of H₂O molecules have two moles O-H bonds. Two moles of the molecule will have four moles of O-H bonds. Forming all those bond will release

  • E(Bonds formed) = 2 × 2 × 463 = 1852 kJ/mol reaction.
  • ΔH(Forming bonds) = - 1852 kJ/mol

Heat of the reaction:

  • \Delta H_{\text{rxn}} = \Delta H(\text{Breaking bonds}) + \Delta H(\text{Forming bonds})\\\phantom{ \Delta H_{\text{rxn}}} = +1371 + (-1852) \\\phantom{ \Delta H_{\text{rxn}}} = -481 \; \text{kJ} / \text{mol}

\Delta H_{\text{rxn}} is negative. As a result, the reaction is exothermic.

3 0
3 years ago
Problem Page Predict the reactants of this chemical reaction. That is, fill in the left side of the chemical equation. Be sure t
Helga [31]

Answer:

CaCl2 + H2O  Ca2+(aq) + 2Cl-(aq)

Explanation:

CaCl2 + H2O  Ca2+(aq) + 2Cl-(aq)

When CaCl2 is dissolved in H2O (water) it will dissociate (dissolve) into Ca+2 and Cl- ions.

The dissolution of calcium chloride is an exothermic process.  

6 0
3 years ago
Calculate the amount of heat required to raise the temperature of a 24 g sample of water from 9°C to 23°C.
borishaifa [10]

Answer:

1400KJ/mol⁻¹

Explanation:

Amount of heat required can be found by:

Q = m × c × ΔT

<em>Where m is the mass, c is the specific heat capacity (4.2KJ for water) and ΔT is the change in temperature.</em>

Q = 24 × 4.2 × (23 - 9)

= 24 × 4.2 × 14

=   1411.2KJ/mol⁻¹

= <u>1400KJ/mol⁻¹</u>  (to 2 significant figures)

7 0
3 years ago
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