What is the density of an object with a mass of 40.0 g and a volume of 80.0 cm3

Which of the following is an example of a physical change in matter?

sineoko [7]

Answer is B.

Explanation:

A physical change is one in which there is no change in chemical composition of a substance. while a process in which there is change in chemical composition it is called a chemical change.

5 0

3 years ago

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6. If 0.500 mol NaN3 react, what mass in grams of nitrogen will result?

lions [1.4K]

Answer:

21 g of N₂ are produced by the decomposition

Explanation:

The reaction is: 2 NaN3 → 2 Na + 3 N2

2 moles of sodium nitride decompose in order to produce 2 moles of Na and 3 moles of nitrogen gas.

According to stoichiometry, ratio is 2:3. Therefore we say,

2 moles of nitride can produce 3 moles of N₂

Then, 0.5 moles of NaN₃ will produce (0.5 . 3) / 2 = 0.75 moles of N₂

We convert the moles to mass, to find the answer

0.75 mol . 28 g / 1 mol = 21 g

7 0

3 years ago

Elias serves a volleyball at a velocity of 16 m/s. The mass of the volleyball is 0.27 kg. What is the height of the volleyball a

frosja888 [35]

Answer:

2,7 m

Explanation:

You can solve this doing an energy balance:

$m*g*h-\frac{1}{2} *m*v^{2} =41,7[J]$

Solving this equation to get h:

$\frac{41,7- \frac{1}{2} *m*v^{2} }{m*g}=h$

Replacing the values and solving brings to 2,7 m

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3 years ago

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Name each of the following species for the following acid-base reactions. (The equilibrium lies to the right in each case, i.e.,

DaniilM [7]

Answer: a) $H_3O^++CH_3O^-\rightleftharpoons CH_3OH+H_2O$

acid : hydronium ion

base : methoxide ion

conjugate acid : methanol

conjugate base: water

b) $CH_3CH_2O^-+HCl\rightleftharpoons CH_3CH_2OH+Cl^-$

acid : hydrogen chloride

base : ethoxide ion

conjugate acid : ethanol

conjugate base: chloride ion

c) $NH_2^-+CH_3OH\rightleftharpoons NH_3+CH_3O^-$

acid : methanol

base : amide ion

conjugate acid : ammonia

conjugate base: methoxide ion

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

The species accepting a proton is considered as a base and after accepting a proton, it forms a conjugate acid.

The species losing a proton is considered as an acid and after loosing a proton, it forms a conjugate base

For the given chemical equation:

a) $H_3O^++CH_3O^-\rightleftharpoons CH_3OH+H_2O$

acid : hydronium ion

base : methoxide ion

conjugate acid : methanol

conjugate base: water

b) $CH_3CH_2O^-+HCl\rightleftharpoons CH_3CH_2OH+Cl^-$

acid : hydrogen chloride

base : ethoxide ion

conjugate acid : ethanol

conjugate base: chloride ion

c) $NH_2^-+CH_3OH\rightleftharpoons NH_3+CH_3O^-$

acid : methanol

base : amide ion

conjugate acid : ammonia

conjugate base: methoxide ion

.

3 0

3 years ago

To melt the ice on your driveway, you can use two moles of rock salt (NaCl) or two moles of calcium chloride (CaCl2). Which solu

Mila [183]

I know it would be calcium chloride, not sure why. Maybe someone could answer that part.

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3 years ago

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