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2 years ago

What is the mass in grams of a sample of 1.20 x 10 22 atoms of mercury?

2 answers:

5 0

4.0g Hg. I may be wrong and I really don't remember how to do it so I am not going to tell you my work, but I tried because I never did good on the chapter in chem.

ArbitrLikvidat [17]2 years ago

5 0

The number of moles in a substance indicates the amount of the substance that contains the same number of particles as 12 g of the Carbon-12 isotope [or equivalent to 6.02 × 10²³] (which is used as a standard in the world of moles).

Now,

if 6.02 × 10²³ atoms are found in 1 mole of mecury
then let 1.20 × 10²² atoms are found in x

⇒ x = (1.20 × 10²²) ÷ (6.02 × 10²³)

= 0.0199 moles

Now, mass = moles × molar mass

∴ mass of Hg = 0.0199 mol × 201 g/mol
= 4.001 g

∴ T<span>he mass in grams of a sample of 1.20 x 10</span>²²<span> atoms of mercury is ~ 4 g</span>

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Which types of changes must follow the law of conservation of mass? (2 points)

Oksana_A [137]

Both Physical and chemical changes.

4 0

2 years ago

What is the molarity of a solution in which 0.732 moles of hcl are dissolved in 0.975 liters of solution?

posledela

Molarity is moles divided by liters so do .732 divided by .975 liters.

6 0

3 years ago

The reaction 2NO(g)+O2(g)−→−2NO2(g) is second order in NO and first order in O2. When [NO]=0.040M, and [O2]=0.035M, the observed

Oksanka [162]

Answer:

(a) The rate of disappearance of $O_{2}$ is: $4.65*10^{-5}$ M/s

(b) The value of rate constant is: 0.83036 $M^{-2}s^{-1}$

(d) The rate will increase by a factor of 3.24

Explanation:

The rate of a reaction can be expressed in terms of the concentrations of the reactants and products in accordance with the balanced equation.

For the given reaction:

$2NO(g)+O_{2}->2NO_{2}$

rate = $-\frac{1}{2} \frac{d}{dt}[NO]$ = $-\frac{d}{dt}[O_{2}]$ = $\frac{1}{2}\frac{d}{dt}[NO_{2}]$ -----(1)

According to the question, the reaction is second order in NO and first order in $O_{2}$ .

Then we can say that, rate = k $[NO]^{2}[O_{2}]$ -----(2)

where k is the rate constant.

The rate of disappearance of NO is given:

$-\frac{d}{dt}[NO]$ = $9.3*10^{-5}$ M/s.

(a) From (1), we can get the rate of disappearance of $O_{2}$ .

Rate of disappearance of $O_{2}$ = $-\frac{d}{dt}[O_{2}]$ = (0.5)*( $9.3*10^{-5}$ ) M/s = $4.65*10^{-5}$ M/s.

(b) The rate of the reaction can be obtained from (1).

rate = $-\frac{1}{2} \frac{d}{dt}[NO]$ = (0.5)*( $9.3*10^{-5}$ )

rate = $4.65*10^{-5}$ M/s

The value of rate constant can be obtained by using (2).

rate constant = k = $\frac{rate}{[NO]^{2}[O_{2}]}$

k = $\frac{4.65*10^{-5}}{(0.040)^{2}(0.035)}$ = 0.83036 $M^{-2}s^{-1}$

k = $\frac{rate}{[NO]^{2}[O_{2}]}$

Substituting the units of rate as M/s and concentrations as M, we get:

$\frac{Ms^{-1} }{M^{3}}$ = $M^{-2}s^{-1}$

(d) The reaction is second order in NO. Rate is proportional to square of the concentration of NO.

$rate\alpha [NO]^{2}$

If the concentration of NO increases by a factor of 1.8, the rate will increase by a factor of $(1.8)^{2}$ = 3.24

5 0

3 years ago

when carbon dioxide is bubbled through lime water the solution first turn milky and to colour less . Explain why these changes o

Annette [7]

Answer:

When excess of carbon dioxide is passed in lime water, calcium carbonate is converted to calcium bicarbonate which is soluble, hence the milkiness due to calcium carbonate disappears.

Explanation:

Ca(OH)2+CO2 → CaCO3 (Milkiness) ↓+H2O

CaCO3+H2O+CO2 → Ca(HCO3)2 (soluble)

5 0

2 years ago

If 3.5 grams of NaN3 decomposed, how many grams of N2 would be produced?

Wewaii [24]

Answer:

5.25 moles.

Explanation:

The decomposition reaction of NaN₃ is as follows :

$2NaN_3(s)\rightarrow 2Na(s)+3N_2(g)$

We need to find how many grams of N₂ produced in the process.

From the above balanced chemical reaction, we conclude that the ratio of moles of sodium azide and nitrogen gas are 2 : 3.

2 moles of sodium azide decomposes to give 3 moles of nitrogen gas. So,

3.5 moles of sodium azide decomposes to give $\dfrac{3}{2}\times 3.5=5.25$ moles of nitrogen gas.

Hence, the number of moles produced is 5.25 moles.

6 0

2 years ago