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3 years ago

0.0200 moles of a compound is found to have a mass of 1.64 g. Find the formula mass of the compound

Chemistry

1 answer:

KatRina [158]3 years ago

3 0

Answer: 82.0 g/mole

Explanation:

Use the units to see that if we divide 1.64 grams by 0.0200 moles, we'll get a number that is grams/mole, the definition of formula mass.

1.64/0.0200 = 82.0 g/mole (3 sig figs)

We can't tell from this alone what the molecular formula might be, but C6H10 (cyclohexene) comes close (82.1 grams/mole).

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What’s the force of a pitching machine on a baseball?

worty [1.4K]

Answer:

The Machine exerts a force of 9N.

Explanation:

Initial velocity (u) = 0 m/s

Final velocity (v) = 30 m/s

Time (t) = 0.5 s

Acceleration (a) = (v-u)/t

= (30-0)/0.5 m/s²

= 30/0.5 m/s²

= 60 m/s²

Mass = 0.15 kg

Force = Mass*Acceleration

= 0.15*60 N

= 9 N

7 0

2 years ago

Alkaline batteries adopted their name from the _____ that is present in the reactions at both the zinc anode and the MnO2 cathod

Paul [167]

Answer:

hydroxide ion

Explanation:

The alkaline battery got this name because it has an alkaline electrolyte of potassium hydroxide.

4 0

2 years ago

Consider this reaction:

aleksklad [387]

Answer: 0.0345 sec

Explanation:

Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.

$Rate=k[H_3PO_4]^2$

k= rate constant = $46.6s^{-1}$

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process

for completion of 20 % of reaction

$t=\frac{2.303}{46.6}\log\frac{0.660}{\frac{20}{100}\times 0.660}$

$t=\frac{2.303}{46.6}\log\frac{0.660}{0.132}$

$t=0.0345sec$

The time taken for the concentration of $H_3PO_4$ to decrease to 20% to its natural value is 0.0345 sec

6 0

3 years ago

Suppose that the mixture in problem 4 is at 15 OC, where the pure vapor pressures are 12.5 mmHg for water and 32.1 mmHg for etha

EleoNora [17]

Answer:

Explanation:

Since we are not given the mole fraction of ethanol and water; we will solve this theoretically.

Using Raoult's Law:

$P_A = (P_o)_A*X_A$

For water:

$(P)w = P_o \times \text{mole fraction of water}$

where $P_o$ of water = 12.5 mmHg

Then, the vapor pressure of water:

$(P)w = 12.5 \ mmHg \times \text{mole fraction of water}$

For ethanol:

$P_E = P_o \times \text {mole fraction of ethanol}$

and the $P_o$ of ethanol = 32.1 mmHg

Then, the vapor pressure of ethanol:

$P_E = 32.1 \ mmHg \times \text {mole fraction of ethanol}$

The total vapor pressure $T_P = P_W + P_E$

The total vapor pressure = $(12.5 \ mmHg \times \text{mole fraction of water}) + (32.1 \ mmHg \times \text {mole fraction of ethanol})$

3 0

3 years ago

I NEED HELP PLEASE! :)

riadik2000 [5.3K]

Answer:

$C_{21} H_{23} NO_{5}$

Explanation:

First thing is we have assume all the percents are grams so we have

68.279g C, 6.2760g H, 3.7898g N, and 21.656g O

Now convert each gram to moles by dividing the the molar mass of each element

68.279g/12.01g= 5.685 moles of C

6.2760g/1.01g= 6.214 moles of H

3.7898g N/14.01g= 0.271 moles of N

21.656g O/ 16.00g= 1.354 moles of O

Now to find the lowest ratios divide all the moles by the smallest number of moles you found, in our case, the smallest moles is 0.271 moles of N so divide everything by that....

5.685 moles/0.271 moles ------> ~21 C

6.214 moles/0.271 moles --------> ~23 H

0.271 moles / 0.271 moles ---------> 1 N

1.354 moles/ 0.271 moles ----------> ~5 O

So the empirical formula is C21H23NO5 $C_{21} H_{23} NO_{5}$

5 0

3 years ago