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3 years ago

Write an informal definition of half-life.

1 answer:

6 0

the time required for the activity of a substance taken into the body to lose one half its initial effectiveness. Informal. a brief period during which something flourishes before dying out.

hope this helps ^^

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A compound with a molar mass of 60g/mol is 40.4% carbon, 6.7% hydrogen and 53.3% oxygen (by mass). determine the emperical and m

Fittoniya [83]

A compound is found to be 40.0% carbon, 6.7% hydrogen and 53.5% oxygen. Its molecular mass is 60. g/mol.
Q1)
Empirical formula is the simplest ratio of whole numbers of components making up a compound.
the percentages have been given, therefore we can calculate for 100 g of the compound.

C H O
Mass in 100 g 40.0 g 6.7 g 53.5 g
Molar mass 12 g/mol 1 g/mol 16 g/mol
Number of moles 40.0/12= 3.33 6.7/1 = 6.7 53.5/16 = 3.34
Divide by the least number of moles
3.33/3.33 = 1 6.7/3.33 = 2.01 3.34/3.33 = 1.00
after rounding off
C - 1
H - 2
O - 1

Empirical formula - CH₂O

Q2)
Molecular formula is the actual number of components making up the compound.
To find the number of empirical units we have to find the mass of one empirical unit.
Mass of one empirical unit = CH₂O - 12 + (1x2) + 16 = 30 g
Mass of one mole of compound = 60 g
Number of empirical units = 60 g / 30 g = 2
Therefore molecular formula - 2(CH₂O)
Molecular formula - C₂H₄O₂

4 0

3 years ago

20 ML of a gas at 200 K is heated until the new volume is 55ML what is the final temperature of the gas

MrRa [10]

Answer:

T2 = 550K

Explanation:

From Charles law;

V1/T1 = V2/T2

Where;

V1 is initial volume

V2 is final volume

T1 is initial temperature

T2 is final temperature

We are given;

V1 = 20 mL

V2 = 55 mL

T1 = 200 K

Thus from V1/T1 = V2/T2, making T2 the subject;

T2 = (V2 × T1)/V1

T2 = (55 × 200)/20

T2 = 550K

8 0

3 years ago

A 48.0g sample of quartz, which has a specific heat capacity of 0.730·J·g−1°C−1, is dropped into an insulated container containi

Butoxors [25]

Answer:

The equilibrium temperature of the water is 26.7 °C

Explanation:

Step 1: Data given

Mass of the sample quartz = 48.0 grams

Specific heat capacity of the sample = 0.730 J/g°C

Initial temperature of the sample = 88.6°C

Mass of the water = 300.0 grams

Initial temperature = 25.0°C

Specific heat capacity of water = 4.184 J/g°C

Step 2: Calculate final temperature

Qlost = -Qgained

Qquartz = - Qwater

Q =m*c*ΔT

Q = m(quartz)*c(quartz)*ΔT(quartz) = -m(water) * c(water) * ΔT(water)

⇒ mass of the quartz = 48.0 grams

⇒ c(quartz) = the specific heat capacity of quartz = 0.730 J/g°C

⇒ ΔT(quartz) = The change of temperature of the sample = T2 -88.6 °C

⇒ mass of water = 300.0 grams

⇒c(water) = the specific heat capacity of water = 4.184 J/g°C

⇒ ΔT= (water) = the change in temperature of water = T2 - 25.0°C

48.0 * 0.730 * (T2-88.6) -300.0 * 4.184 *(T2 - 25.0)

35.04(T2-88.6) = -1255.2 (T2-25)

35.04T2 -3104.544 = -1255.2T2 + 31380

1290.24T2 = 34484.544

T2 = 26.7 °C

The equilibrium temperature of the water is 26.7 °C

8 0

3 years ago

Put these events in the correct order

zloy xaker [14]

Answer:

Computer, Microprocessor, Cell Phone, WWW, iPhone

Explanation:

i just did it and got it correct

6 0

3 years ago

Read 2 more answers

A train travels 803.98 meters in 1 minute what is the trains average rate of speed

TEA [102]

Answer:

Approximately 13.4 meters per second (m/s)

Explanation:

We can divide the distance by 60 seconds to find the trains average rate of speed.

803.98 / 60 ≈ 13.4

Best of Luck!

7 0

3 years ago