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3 years ago

15

a chemical reaction was used to separate a sample into its components what conclusion about the sample can be formed A it was a

pure substance it was a compound Bit was a heterogeneous mixture it was a homogeneous mixture

1 answer:

raketka [301]3 years ago

3 0

It was a compound, hence it needed to be separated into its individual components by chemical means.

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If in a redox reaction oxidation state of elements decreases or looses electron(s), the element is said to be oxidized. Hope this helps you!

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3 years ago

Please helpp neep asap ik its late at night but i just need this one page and i can rest

stich3 [128]

Answer:

15. Velocity = 3 X 10^8

Distance = 1580 m

time = distance / velocity

<em>t = 1580 / 3 * 10^8</em>

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<em>t = 158 * 10^-7/3</em>

<u>t = 5.26 * 10^-8 seconds </u>

16. Converting the distance to 'm'

Given distance (in miles), multiplying by 1.609 to convert to km and also multiplying by 1000 to convert to 'm'

s= 4.8 * 1.609 * 10^7 * 1000

v = 3 * 10^8

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t = 1.6 * 1609 * 10^-1

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17. Mass in 1 tsp of medicine = 5 mL at a density of 25 mg/mL

Mass in 1 tsp of medicine = 5 * 25 = 125 mg

Mass prescribed by the doctor = 375 mg

Number of table spoons required = Mass prescribed / Mass in 1 tsp

N = 375/125 = 3 table spoons of the medicine

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19. Volume of 10 drops = 1 mL

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Water leaked in 1440 minutes = 1440 * 1/2 = 720

0.720 L (720 mL) Water leaked from the faucet in a day

<em>Kindly mark Brainliest, Thanks</em>

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4 years ago

Which event would be impossible to explain by using John Dalton’s model of the atom?

schepotkina [342]

The scientist thought that the atom was the smallest particle in the universe is John Dalton. He established the atomic theory which consists of five; elements are made of extremely small particles called atoms, atoms of different element have different sizes, mass and physic – chemical properties, atoms cannot be divided further, destroyed or created, atoms can combine to form compounds and in chemical reaction, atoms can be combined, separated or rearranged. Hope this helps!!

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4 years ago

Read 2 more answers

Radioactive carbon-14 has a half life of 5730 years. Suppose a peice of wood has a decay rate of 15 disintegrations per minute.

Tom [10]

Answer:

$\large \boxed{\text{2920 yr}}$

Explanation:

Two important formulas in radioactive decay are

$(1) \qquad t_{\frac{1}{2}} = \dfrac{\ln 2}{k}\\\\(2) \qquad \ln \left(\dfrac{N_{0}}{N}\right) = kt$

1. Calculate the decay constant k

$\begin{array}{rcl}t_{\frac{1}{2}} &=& \dfrac{\ln 2}{k}\\\\\text{1530 yr} &= &\dfrac{\ln 2}{k}\\\\k & = & \dfrac{\ln 2}{\text{1530 yr}}\\\\& = & 4.530 \times 10^{-4} \text{ yr}^{-1}\\\end{array}$

2. Calculate the time

$\begin{array}{rcl}\ln \left(\dfrac{N_{0}}{N}\right) &= &kt \\\\\ln \left(\dfrac{15}{4}\right) &= &4.530 \times 10^{-4} \text{ yr}^{-1}\times t \\\\\ln 3.75 &= &4.530 \times 10^{-4} \text{ yr}^{-1}\times t \\t &= &\dfrac{\ln 3.75}{4.530 \times 10^{-4} \text{ yr}^{-1}}\\\\& = & \textbf{2920 yr}\\\end{array}\\\text{It would take $\large \boxed{\textbf{2920 yr}}$ for the rate to decrease to 4 dis/min.}$

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4 years ago

3) Explain why the standard enthalpy of vaporization, (Delta)Hvap, values for each set of compounds below are not the same.

Amanda [17]

Answer:

a. CH4 is only held together by London dispersion forces since any dipoles cancel out due to symmetry. On the other hand H2O has strong hydrogen bonds

b. PH3 has dipole-dipole forces while NH3 is held together by stronger hydrogen bonding

c. C2H6 and C3H8 . Both substances are held together by London dispersion forces since any dipoles cancel out due to symmetry. However C3H8 has the stronger London dispersion forces of the two because it is a larger molecule,

d. BH3 is held together by London dispersion forces since any dipoles cancel out due to symmetry while OF2 is held together by stronger dipole-dipole forces

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3 years ago