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Chemistry

Asked by Lexie

What forces are overcome when substance a melts

When an object is solid, it is held together by a strong electrostatic force, as you heat the object it gains energy causing the particles to move, this caused the particles to move away from eachother and spread out causing the solid to melt and become liquid I think that's it, there might be more as I am not a chemistry expert but electrostatic is the main one

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Lauren Holland
·

274 students helped

Chemistry

Asked by Chrisshelle

How many molecules are in 123.2g of CO2

First calculate the number of moles of CO2: Moles = mass/Mr Moles (CO2) = 123.2/44 = 2.8 Avogadro’s constant is the number of entities (molecules) in one mole of any substance, in other words there are 6.022 x 10^23 molecules in one mole of any substance. So in 123.2g of CO2, there are 2.8 moles So 2.8 x 6.022 x 10^23 = 1.69x10^24

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Haziq Ibrahim
·

214 students helped

Chemistry

Asked by Kenia

How many moles of NaHCO3 are in 44g

Moles = Mass / Mr Mass = 44g Mr = Na (1x23.0) + H (1x1.0) + C (1 x 12.0) + O (3 x 16.0) = 84.0 Moles = 44g / 84.0 = 0.524 moles

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Hanaan Ahmed
·

287 students helped

Chemistry

Asked by Kiah

Why is sodium less reactive than potassium

The Sodium atom is smaller than the Potassium atom. This means that the electrons in the sodium atom are closer to the nucleus - it has a stronger electrostatic force of attraction. This also means that it is hard for Sodium to lose an electron. The electrons in the Potassium atom are further away from the nucleus, therefore making it easier to lose them (it has weak electrostatic forces of attra... more

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Rhea Hossein
·

202 students helped

Chemistry

Asked by Vinita

What is the best way to revise for chemistry alevel?

First go through and make sure you understand the content. A-Level Chemistry is very big on concepts! Then, and I really can't stress this enough, do as many questions as possible. Chemistry is an applied science, memorising alone won't really get you far. By answering questions you'll understand what details you've missed out and the overall language + keywords they want you to use in your exam.

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Ibrahim Dangra
·

1.2k students helped

Chemistry

Asked by Anisa

Identify two sulphur containing reduction products formed when concentrated sulphuric acid oxidises iodide ions

Iodide ions are such a powerful reducing agent that they reduce the (SO4) 2- ions to SO2, and then to elemental Sulphur, and then finally to H2S

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Damon Marlow
·

149 students helped

Chemistry

Asked by Cooper

Describe the structure of lithium chloride.

First off, do you know what type of bonding is in lithium chloride? Since it’s made of a metal and a non-metal, it’s gonna be ionic bonding. Which means electrons are being transferred from one atom to another right? Which atom is going to lose electrons and which will gain, and how many? Lithium, being in group 1 has 1 electron in the outer shell. Chlorine in group 7 will have 7 electrons in t... more

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Ibrahim Dangra
·

1.2k students helped

Chemistry

Asked by Akinda

Pottqsium iodide with cl2 gas reaction

2KI + Cl2 -> 2KCl + I2

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Fiona Clark
·

25 students helped

Chemistry

Asked by Ad

Similarity between chemical bond and intermolecular force

A bond binds compounds/atoms by transfer or sharing of electrons (ionic and covalent). A force (intermolecular) is a weaker interaction between compounds/atoms. A similarity would be that they both involve the attraction of compounds to one another

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Haziq Ibrahim
·

214 students helped

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