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3 years ago

How many valance electrons does He need to get to 8

Chemistry

1 answer:

mote1985 [20]3 years ago

5 0

Answer:

Any element in group 18 has eight valence electrons (except for helium, which has a total of just two electrons

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Potential or kinetic? when the light switch is __________ it is potential energy

faltersainse [42]

When the light switch is flipped it has kinetic energy, when it is idle it has potential energy.

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3 years ago

A 3.4 g sample of sodium hydrogen carbonate is added to a solution of acetic acid weighing 10.9 g. The two substances react, rel

natima [27]

Answer: 2.7 grams

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

$NaHCO_3(aq)+CH_3COOH(aq)\rightarrow CH_3COONa(aq)+H_2O(l)+CO_2(g)$

Given: mass of sodium hydrogen carbonate = 3.4 g

mass of acetic acid = 10.9 g

Mass of reactants = mass of sodium hydrogen carbonate+ mass of acetic acid = 3.4 + 10.9= 14.3 g

Mass of reactants = Mass of products in reaction vessel + mass of carbon dioxide (as it escapes)

Mass of carbon dioxide = 14.3 - 11.6 =2.7 g

Thus the mass of carbon dioxide released during the reaction is 2.7 grams.

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3 years ago

? C+? O2 +? CO2,

IRINA_888 [86]

Look at the mole ratio in the balanced equation

2CO + O2 ==> 2CO2

3.44 mol O2 x 2 mol CO/mol O2 = 6.88 moles CO

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3 years ago

Which substance exists as a molecular compound? a sulfate ion, calcium chloride, methanol, oxygen

Viktor [21]

The substance would be:Methanol (ch40)

5 0

3 years ago

Read 2 more answers

Please help me. Chemistry

Wewaii [24]

Answer:

element S is argon and element T is potassium.

4. B

5. D

Explanation:

in an element in periodic table number of elctrons and protons are same.

4. since element S has 18 protons so its atomic number must be 18 so the element is Argon which is the last element of period 4 so the next element will go to period 4 with one extra shell and since the atomic number of next element is 19 the element is Potassium. therefore T is Potassium.

5. number of nucleons in an atom is the number of protons and neutons combined together in an nucleus

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4 years ago