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2 years ago

What element has 7 valence electrons

Chemistry

1 answer:

PolarNik [594]2 years ago

7 0

I believe the answer would be halogens

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Plz help :(

ziro4ka [17]

<h2>Answer:0.5 moles,1 mole</h2>

Explanation:

$Sr(NO_{3})_{2}$ is readily soluble in water.

$Sr(NO_{3})_{2}$ dissolves in water to give $Sr^{2+}$ ions and $NO_{3}^{-}$ ions.

The reaction is

$Sr(NO_{3})_{2}$ → $Sr^{2+}$ $+2NO_{3}^{-}$

So, $1$ mole of $Sr(NO_{3})_{2}$ gives $1$ mole of $Sr^{2+}$ and $2$ moles of $NO_{3}^{-}$ .

So, $0.5$ moles of $Sr(NO_{3})_{2}$ gives $0.5$ moles of $Sr^{2+}$ and $1$ mole of $NO_{3}^{-}$ .

5 0

3 years ago

Select True or False: Pi bonds are covalent bonds in which the electron density is concentrated above and below a plane containi

anzhelika [568]

Answer:

True

Explanation:

In pi bonds, the electron density concentrates itself between the atoms of the compound but are present on either side of the line joining the atoms. Electron density is found above and below the plane of the line joining the internuclear axis of the two atoms involved in the bond.

Pi bonds usually occur by sideways overlap of atomic orbitals and this leads to both double and triple bonds.

3 0

2 years ago

What are the two categories of chemical sedimentary rock?

AnnyKZ [126]

Calcite and calcite?

4 0

2 years ago

A balanced chemical equation is shown below

IrinaVladis [17]

Answer:

The answer is A.

Explanation:

C6H12O6 + 6O2 -> 6CO2 + 6H20

C6H12O6 + 6O2 -> 6CO2 + 6H20At the reactant side, there are 6 carbon atoms, 12 hydrogen atoms and 18 oxygen atoms.

atoms, 12 hydrogen atoms and 18 oxygen atoms.At product side, there are 6 carbon atoms, 12 hydrogen atoms and 18 oxygen atoms.

(In a balanced equation, the no. of atoms on the reactant side must be equal to the no. of atoms on the product side)

4 0

3 years ago

What is the total amount of heat released when 94.0 g water at 80.0 °C cools to form ice at −30.0 °C?

Wewaii [24]

Answer:

The total amount of heat released is 68.7 kJ

Explanation:

Given that:

mass of water = 94.0 g

moles of water = 94 / 18.02 = 5.216

80⁰C ------> 0⁰C --------> -30⁰C

Q1 = m Cp dT

= 94 x 4.184 x (0 - 80)

= -31463.68 J

= -31.43 kJ

Q2 = 6.01 x 10^3 x 5.216

= - 31348.16 J

= -31.35 kJ

Q3 = - 94 x 2.09 x 30

= - 5893.8 J

= -5.894 kJ

Total heat = Q1 + Q2 + Q3 = -31.43 kJ + (-31.35 kJ ) + (-5.894 kJ ) = -68.7 kJ

Total heat released = -68.7 kJ

Note that the "negative sign" simply indicates heat released, therefore no need to put it in the answer.

6 0

2 years ago