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The density of platinum is 21.45 g/cm3. What is the volume of a platinum sample with a mass of 11.2 g?

Answers

Answer 1

Answer:

Answer: 0.522cm3

Explanation:

Mass = 11.2g

Density = 21.45 g/cm3

Volume =?

Volume = Mass /Density

Volume = 11.2 / 21.45

Volume = 0.522cm3

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What is the maximum mass in grams of NH3 that can be produced by the reaction of of 2.5 g N2 with 2.5 g of H2 via the equation below?N2 (g) + 3 H2 (g) → 2 NH3 (g)
Hi ! Could someone help me out with this last part to my chemistry practice ? Thank you !
How many mL of 0.100 M NaOH are needed to neutralize 50.00 mL of a 0.150 M solution of CH3CO2H, a monoprotic acid? How many mL of 0.100 M NaOH are needed to neutralize 50.00 mL of a 0.150 M solution of CH3CO2H, a monoprotic acid? a. 37.50 mL b. 50.00 mL c. 75.00 mL d. 100.00 mL e. 25.00 mL
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A 3.25 L solution is prepared by dissolving 285 g of BaBr2 in water. Determine the molarity.

If a 0.2g of oil consumed 1ml of sodium thiosulphate, calculate its iodine value and classify the oil?

Answers

Iodine value is a measure of the degree of unsaturation in fats and oils. It is essentially the number of grams of iodine consumed by 100 g of fat. If the iodine number is in the range of 0-70 then it is a fat, any value above 70 is considered an oil.

Formula:

Iodine number = (ml of 0.1 N Thiosulphate blank- ml of 0.1N thiosulphate test) * 12.7 *100/1000* wt of sample

vol of thiosulphate required to titrate test sample (given oil) = 1 ml

wt of sample = 0.2 g

Information on the volume of thiosulphate required to titrate the blank solution is essential for calculation.

Iodine number = (X-1.0) * 12.7 * 100/1000* 0.2 = (X-1.0)*6.35

NEED HELP!
C=46.67%, H=4.48%, N=31.10%, O=17.76%.
The molecular weight is 180.16g/mol.

Answers

Answer:

$C_7H_8N_4O_2$

Explanation:

Hello!

In this case, since the determination of an empirical formula is covered by first computing the moles of each atom as shown below:

$n_C=(46.47g)/(12g/mol)=3.9mol\n\n n_H=(4.48g)/(1g/mol) =4.5mol\n\nn_N=(31.10g)/(14g/mol) =2.2mol\n\nn_O=(17.76g)/(16g/mol) =1.1mol$

Now, we divide each moles by the fewest moles (those of oxygen), to obtain the subscripts in the empirical formula:

$C:(3.9)/(1.1)=3.5 \n\nH:(4.5)/(1.1)=4 \n\nN:(2.2)/(1.1) =2\n\nO:(1.1)/(1.1) =1$

Thus, the empirical formula, taken to the nearest whole subscript is:

$C_7H_8N_4O_2$

Whose molar mass is 180.16, therefore the empirical formula is the same to the molecular one.

Best regards!

How many grams of solid sodium cyanide should be added to 1.00 L of a 0.119 M hydrocyanic acid solution to prepare a buffer with a pH of 8.809

Answers

Answer:

1.62 g

Explanation:

Given that:

Concentration of HCN = 0.119 M

Assuming the ka 4.00 × 10⁻¹⁰

The pKa of HCN (hydrocyanic acid) = -log (Ka)

= - log ( 4.00 × 10⁻¹⁰)

= 9.398

pH of buffer = 8.809

Using Henderson Hasselbach equation:

$pH = pKa + log ([conjugate\ base ])/(acid)$

$pH = pKa + log ([CN^-])/([HCN])$

$8.809 = 9.398 +log ([CN^-])/([HCN])$

$log ([CN^-])/([HCN])= 8.809 - 9.398$

$log ([CN^-])/([HCN])= -0.589$

$([CN^-])/([HCN])= 0.2576$

[CN^-] = 0.2576[HCN]

[CN^-] = 0.2756 (0.119) L

[CN^-] = 0.033 M

∴

The amount of NaCN (sodium cyanide) is calculated as follows:

$= 1.00 L * (0.033 \ mol \ NacN )/(1 \ L ) * (49.01 \ g)/(1 \ mol \ of \ NacN)$

= 1.62 g

You are given mixture made of 290 grams of water and 14.2 grams of salt. Determine the % by mass of salt in the salt solution.

Answers

Answer:

Solution is 4.67% by mass of salt

Explanation:

% by mass is the concentration that defines the mass of solute in 100g of solution.

In this case we have to find out the mass of solution with the data given:

Mass of solution = Mass of solute + Mass of solvent

Solute: Salt → 14.2 g

Solvent: Water → 290 g

Solution's mass = 14.2 g + 290g = 304.2 g

% by mass = (mass of solute / mass of solution) . 100

(14.2 g / 304.2g) . 100 = 4.67 %

An imaginary line dividing the earth's surface into two hemisphere the northern and southern hemisphere, it is locatedat 0⁰, which of the following imaginary lines is being described? a.equator b.latitude c.longitude d.prime meridian

Answers

Answer:

A. Equator

Explanation:

The equator is located in the centre of the Earth, dividing the northern and southern hemispheres.

Answer:

Equator because equator divides the earth into Northern and Southern hemisphere.

Which molecule does not exhibit hydrogen bonding?a. HFb. CH3NH2c. CH2F2d. HOCH2CH2OH

Answers

Answer:

Explanation:

Hydrogen bonds are weak intermolecular forces. They are the strongest kind of intermolecular forces, although they are weaker than the covalent bonds.

Hydrogen bonds arise from molecules which contain a hydrogen atom which is bonded to one of the most electronegative elements such as N, O or F.

(a) HF, → has H-F bond

(b) CH₃NH₂, → has N-H bond

(d) HOCH₂CH₂OH, → has O-H bond

Therefore, only CH₂F₂ does not exhibit hydrogen bonding.

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