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3 years ago

Good day pleases help

Chemistry

2 answers:

evablogger [386]3 years ago

7 0

The answer is b. Wolves work together

klemol [59]3 years ago

6 0

I can’t see the choices can you take another picture of this assignment please so i can help you

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When 50.0 mL of 1.27 M of HCl(aq) is combined with 50.0 mL of 1.32 M of NaOH(aq) in a coffee-cup calorimeter, the temperature of

sergij07 [2.7K]

Answer:

-55.9kJ/mol is the change in enthalpy of the reaction

Explanation:

In the reaction:

HCl(aq) + NaOH(aq) → H₂O(l) + NaCl

Some heat is released per mole of reaction.

To know how many moles reacts we need to find limiting reactant:

Moles HCl = 0.050L ₓ (1.27mol / L) = 0.0635 moles HCl

Moles NaOH = 0.050L ₓ (1.32mol / L) = 0.066 moles NaOH

As there are more moles of NaOH than moles of HCl, HCl is limiting reactant and moles of reaction are moles of limiting reactant, 0.0635 moles

Using the coffee-cup calorimeter equation we can find how many heat was released thus:

Q = C×m×ΔT

Where Q is heat released, C is specific heat of the solution (4.18J/g°C), m is mass of solution (100g because there are 100mL of solution -50.0mL of HCl and 50.0mL of NaOH- and density is 1g/mL) and ΔT is change in temperature (8.49°C)

Replacing:

Q = 4.18J/g°C×100g×8.49°C

Q = 3548.8J of heat are released in the reaction

Now, change in enthalpy, ΔH, is equal to change in heat (As is released heat ΔH < 0) per mole of reaction, that is:

ΔH = Heat / mol of reaction

ΔH = -3548.8J / 0.0635 moles of reaction

Negative because is released heat.

ΔH = -55887J / mol

ΔH =

<h3>-55.9kJ/mol is the change in enthalpy of the reaction</h3>

3 0

3 years ago

If an atom contains 11 protons and 12 neutrons, what is its atomic number?

Sergio039 [100]

Atomic number is Z. Z=number of protons, so Z=11

4 0

3 years ago

Read 2 more answers

Compared to the ideal bond angle, the actual/real bond angle in a molecule of water will be:______.

inna [77]

Answer: d. smaller.

Explanation:

Hybridization :

$N=\frac{1}{2}[V+N+A-C]$

N = number of electrons

where, V = number of valence electrons present in central atom i.e. oxygen = 6

N = number of monovalent atoms bonded to central atom=32

C = charge of cation = 0

A = charge of anion = 0

The number of electrons is 4 that means the hybridization will be $sp^3$ and the electronic geometry of the molecule will be tetrahedral. The bond angle for tetrahedral geometry is $109.5^0$

But as there are two atoms around the central oxygen, the third and fourth position will be occupied by lone pair of electrons. The repulsion between lone and bond pair of electrons is more and hence the molecular geometry will be bent and the bond angle will be smaller than expected and is $104.5^0$