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2 years ago

Describe how calcium and fluorine bond together to form calcium fluoride

2 answers:

monitta2 years ago

5 0

Answer: A transfer of electrons occurs when fluorine and calcium react to form an ionic compound. This is because calcium is in group two and so forms ions with a two positive charge. ... A pairs of shared electrons makes one covalent bond. The compound formed is known as a molecule***

sukhopar [10]2 years ago

4 0

Answer:

A transfer of electrons occurs when fluorine and calcium react to form an ionic compound. This is because calcium is in group two and so forms ions with a two positive charge. ... A pairs of shared electrons makes one covalent bond. The compound formed is known as a molecule.

Explanation:

i think this is right :)

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3. Burns from boiling water can be severe, caused by the transfer of energy from the boiling water to the

Free_Kalibri [48]

Answer:

Q = 3937.56 J

Explanation:

Heat transferred due to change in temperature is given by :

$Q=mc\Delta T$

c is the specific heat of water, c=4.18 J/g-°C

We have, m = 15 g, $T_i=100^{\circ} C\ \text{and}\ T_f=37.2^{\circ} C$

So,

$Q=15\times 4.18\times (37.2-100)\\Q=-3937.56\ J$

Hence, 3937.56 J of heat is transferred.

8 0

3 years ago

explain how the number of valence electrons in atoms relate to their bonding with other atoms to form molecules ?????

Westkost [7]

valence electrons are the number of electrons in the outer shell. there can only be 8 electrons in the outer shell. The number of valence electrons can be used to determine how many bonds are needed.

For example: H2O

O (oxygen) has 6 valence electrons
H (hydrogen) has 1 valence electron

O needs 2 more electrons to be stable
H needs 1 more electron to be stable

O forms one bond with two H atoms to form H2O.

5 0

2 years ago

What is the pH of a 0.640 M solution of C₅H₅NHBr (Kb of C₅H₅N is 1.7 × 10⁻⁹)?

Elden [556K]

The pH of a 0.64 M solution of pyridine (C₅H₅N) is 9.52.

A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid and higher values more alkaline.

The equation for the protonation of the base pyridine is the following:

C₅H₅N + H₂O ⇄ C₅H₅NH⁺ + OH⁻ (1)

Kb = 1.7 × 10⁻⁹ (Given)

To calculate the pH of the solution we need to use the following equation:

pH + pOH = 14

pH = 14 - pOH

=14 - [-log[OH⁻]]

= 14 + log[OH⁻]

Now, we need to find the concentration of the OH⁻ ions. Since pyridine is a weak base, at the equilibrium we have (eq 1):

C₅H₅N + H₂O ⇄ C₅H₅NH⁺ + OH⁻

0.64 - x x x

After entering the values of [C₅H₅N] = 0.64-x, [C₅H₅NH⁺] = x, and [OH⁻] = x, into equation (2) we can find the concentration of OH⁻:

1.7 × 10⁻⁹ =[C₅H₅NH⁺] [OH⁻] / [C₅H₅N]

= x . x / 0.64-x

1.7 × 10⁻⁹ (0.64-x) - x² = 0

Solving the above quadratic equation for x, we have :

x₁ = -3.32 x 10⁻⁵
x₂ = 3.32 x 10⁻⁵

Now, We can calculate the pH, after taking the positive value, x₂, (concentrations cannot be negative) and entering into above equation :

pH = 14 + log[OH⁻]

= 14 + log (3.32 x 10⁻⁵)

= 9.52

Therefore, the pH of the solution of pyridine is 9.52.

Find more about pH here:

brainly.com/question/8834103?referrer=searchResults

#SPJ1

3 0

1 year ago

A pan containing 20.0 grams of water was allowed to cool from a temperature of 95.0 °C. If the amount of heat released is 1,200

Sedbober [7]

Answer:

81°C.

Explanation:

To solve this problem, we can use the relation:

Q = m.c.ΔT,

where, Q is the amount of heat released from water (Q = - 1200 J).

m is the mass of the water (m = 20.0 g).

c is the specific heat capacity of water (c of water = 4.186 J/g.°C).

ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = final T - 95.0°C).

∵ Q = m.c.ΔT

∴ (- 1200 J) = (20.0 g)(4.186 J/g.°C)(final T - 95.0°C ).

(- 1200 J) = 83.72 final T - 7953.

∴ final T = (- 1200 J + 7953)/83.72 = 80.67°C ≅ 81.0°C.

So, the right choice is: 81°C.

7 0

3 years ago

How many kilojoules are released when 116 g of Cl2 reacts with silicon? Si(s)+2Cl2(g)→SiCl4(g)ΔH=−657kJ

alexandr402 [8]

Answer:- 537 kJ of heat is released.

Solution:- For the given equation, $\Delta H$ is -657 kJ and the coefficient of $Cl_2$ in the balanced equation is 2. It means 657 kJ of heat is released when 2 moles of chlorine are used. We need to calculate the heat released when 116 g of $Cl_2$ are used.

Grams of chlorine are converted to moles and then multiplied by the $\Delta H$ value and divided by the coefficient of chlorine and the set could be shown using dimensional analysis as:

$116gCl_2(\frac{1mol}{70.9g})(\frac{657kJ}{2mol})$

= 537.46 kJ

If we use the correct sig figs then it needs to be round off to three sig figs as the given grams of chlorine has only three sig figs. So, 537 kJ of heat is released.

6 0

2 years ago