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4 years ago

I NEED HELP PLEASE, THANKS! :)

Chemistry

1 answer:

Free_Kalibri [48]4 years ago

7 0

Answer:

Explanation:

Metallic character increases across a period to the left and downwards.

If you look at the periodic table, Cs is lower and more towards the left.

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When a mineral was heated in a Bunsen flame to constant mass, a colourless gas that turned lime water milky was evolved. The rem

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Vigorous effervescence can be seen only in C

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3 years ago

What volume of a 0.35M solution of sodium chloride could be formed with 25 grams of NaCl?

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Answer:

A concentrated solution has a greater amount of dissolved solute than a dilute solution. Explanatio ... More

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2 years ago

When 0.250 moles of KCl are added to 200.0 g of water in a constant pressure calorimeter a temperature change is observed. Given

777dan777 [17]

Explanation:

Upon dissolution of KCl heat is generated and temperature of the solution raises.

Therefore, heat generated by dissolving 0.25 moles of KCl will be as follows.

$17.24 kJ/mol \times 0.25 mol$

= 4.31 kJ

or, = 4310 J (as 1 kJ = 1000 J)

Mass of solution will be the sum of mass of water and mass of KCl.

Mass of Solution = mass of water + (no. of moles of KCl × molar mass)

= 200 g + $(0.25 mol \times 54.5 g/mol)$

= 200 g + 13.625 g

= 213.625 g

Relation between heat, mass and change in temperature is as follows.

Q = $mC \Delta T$

where, C = specific heat of water = $4.184 J/g^{o}C$

Therefore, putting the given values into the above formula as follows.

Q = $mC \Delta T$

4310 J = $213.625 g \times 4.184 J/g^{o}C \times \Delta T$

$\Delta T = 4.82^{o}C$

Thus, we can conclude that rise in temperature will be $4.82^{o}C$ .

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3 years ago

Analysis of an ore of calcium shows that it contains 13.61 g calcium and 21.77 g oxygen in a 46.28-g sample. Calculate the perce

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Answer:

29.41% of Calcium and 47.04% of Oxygen

Explanation:

The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.

The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:

13.61g / 46.28g * 100 = 29.41% of Calcium

And percent composition of Oxygen is:

21.77g / 46.28g * 100 = 47.04% of Oxygen

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3 years ago

Why was it so important that the scientist investigating the atom be young and unattached to existing scientific thinking

tatiyna

Answer:

so they can find the aswer and not get hurt

Explanation:

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3 years ago