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3 years ago

1) What happened around 10,000 years ago that changed the way many humans live?

Chemistry

2 answers:

ziro4ka [17]3 years ago

6 0

Answer:

Explanation:

hope everything is good!!

love history [14]3 years ago

3 0

The answer is C

Hope it helps ;)

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THE RIGHT ANSWER WILL RECIEVE A BRAINLEST AND POINTS!!!

earnstyle [38]

If you drop a bath bomb into water, then it will fizz because a chemical reaction is taking place.

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3 years ago

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Does anyone have answers of a worksheet called “ Intro to Graphs” Chemquest 2?

r-ruslan [8.4K]

Answer:

Explanation:

Because I have lost and I dont know where is the worksheet

8 0

3 years ago

An iron ore sample weighing 0.5562 g is dissolved HCl (aq), and the iron is obtained as Fe2 in solution. This solution is then t

erik [133]

Answer:

$\% Fe^{+2}=70%$

Explanation:

Hello,

In this case, we could considering this as a redox titration:

$Fe^{+2}+(Cr_2O_7)^{-2}\rightarrow Fe^{+3}+Cr^{+3}$

Thus, the balance turns out (by adding both hydrogen ions and water):

$Fe^{+2}\rightarrow Fe^{+3}+1e^-\\(Cr_2^{+6}O_7)^{-2}+14H^++6e^-\rightarrow 2Cr^{+3}+7H_2O\\\\6Fe^{+2}+(Cr_2^{+6}O_7)^{-2}+14H^++6e^-\rightarrow Cr^{+3}+7H_2O+6Fe^{+3}+6e^-$

Thus, by stoichiometry, the grams of Fe+2 ions result:

$m_{Fe^{+2}}=0.04021\frac{molK_2Cr_2O_7}{L}*0.02872L*\frac{6molFe^{+2}}{1molK_2Cr_2O_7}*\frac{56gFe^{+2}}{1molFe^{+2}}=0.388gFe^{+2}$

Finally, the mass percent is:

$\% Fe^{+2}=\frac{0.388g}{0.5562g}*100\%\\ \% Fe^{+2}=70%$

Best regards.

8 0

3 years ago

Calculate the vapor pressure in torr of a solution containng 24.5 g of glycerin (C3H8O3) in 135 mL water at 30.0* C; the vapor p

Otrada [13]

Psolution = X · PH_20
= 0.966 · 31.8 torr
= 30.7 torr

3 0

2 years ago

Which isotope will spontaneously decay and emit particles with a charge of +2?

VikaD [51]

Answer: The correct option is 4.

Explanation: All the options will undergo some type of radioactive decay processes. There are 3 decay processes:

1) Alpha decay: It is a decay process in which alpha particle is released which has has a mass number of 4 and a charge of +2.

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha$

2) Beta-minus decay: It is a decay in which a beta particle is released. The beta particle released has a mass number of 0 and a charge of (-1).

$_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta$

3) Beta-plus decay: It is a decay process in which a positron is released. The positron released has a mass number of 0 and has a charge of +1.

$_Z^A\textrm{X}\rightarrow _{Z-1}^A\textrm{Y}+_{+1}^0\beta$

For the given options:

Option 1: This nuclei will undergo beta-plus decay process to form $_{25}^{53}\textrm{Mn}$

$_{26}^{53}\textrm{Fe}\rightarrow _{25}^{53}\textrm{Mn}+_{+1}^0\beta$

Option 2: This nuclei will undergo beta-minus decay process to form $_{80}^{198}\textrm{Hg}$

$_{79}^{198}\textrm{Au}\rightarrow _{80}^{198}\textrm{Hg}+_{-1}^0\beta$

Option 3: This nuclei will undergo a beta minus decay process to form $_{56}^{137}\textrm{Ba}$

$_{55}^{137}\textrm{Cs}\rightarrow _{56}^{137}\textrm{Ba}+_{-1}^0\beta$

Option 4: This nuclei will undergo an alpha decay process to form $_{85}^{216}\textrm{At}$

$_{87}^{220}\textrm{Fr}\rightarrow _{85}^{216}\textrm{At}+_2^4\alpha$

Hence, the correct option is 4.

7 0

4 years ago

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