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1 year ago

12

In a chemical hot pack, iron powder and oxygen react to form iron oxide in the presence of a catalyst. This reaction causes the

temperature of the hot pack to increase. This process is

1 answer:

nadezda [96]1 year ago

6 0

Answer:

exothermic

Explanation:

exothermic reactions give off heat.....or the temp of the substances increases

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A car is traveling 83.3 kilometers per hour. What is its speed in miles per minute? One kilometer = 0.62 miles.

Leya [2.2K]

Hi. 2fouls! :)

First convert the number from kilometer to miles:
$83.3*0.62$
$=51.646 miles$

Now to find the miles per minutes,divide the miles per hours by 60 (the amount of minutes in an hour.)

$51.646/60$
$=0.860766667$

The car is travelling at a speed of 0.860766667 miles/minute.

Hope this helps.
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3 years ago

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Identify this reaction

Natasha2012 [34]

Answer:

d a a

Explanation:

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2 years ago

Which of the following possess the greatest concentration of hydroxide ions?

jek_recluse [69]

Answer : The correct option is (d) a solution of 0.10 M NaOH

Explanation :

<u>(a) a solution of pH 3.0</u>

First we have to calculate the pOH.

$pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-3.0=11$

Now we have to calculate the $OH^-$ concentration.

$pOH=-\log [OH^-]$

$11=-\log [OH^-]$

$[OH^-]=1.0\times 10^{-11}M$

Thus, the $OH^-$ concentration is, $1.0\times 10^{-11}M$

<u>(b) a solution of 0.10 M $NH_3$ </u>

As we know that 1 mole of $NH_3$ is a weak base. So, in a solution it will not dissociates completely.

So, the $OH^-$ concentration will be less than 0.10 M

<u>(c) a solution with a pOH of 12.</u>

We have to calculate the $OH^-$ concentration.

$pOH=-\log [OH^-]$

$12=-\log [OH^-]$

$[OH^-]=1.0\times 10^{-12}M$

Thus, the $OH^-$ concentration is, $1.0\times 10^{-12}M$

<u>(d) a solution of 0.10 M NaOH</u>

As we know that $NaOH$ is a strong base. So, it dissociates to give $Na^+$ ion and $OH^-$ ion.

So, 0.10 M of $NaOH$ in a solution dissociates to give 0.10 M of $Na^+$ ion and 0.10 M of $OH^-$ ion.

Thus, the $OH^-$ concentration is, 0.10 M

<u>(e) a $1\times 10^{-4}M$ solution of $HNO_2$ </u>

As we know that 1 mole of $HNO_2$ in a solution dissociates to give 1 mole of $H^+$ ion and 1 mole of $NO_2^-$ ion.

So, $1\times 10^{-4}M$ of $HNO_2$ in a solution dissociates to give $1\times 10^{-4}M$ of $H^+$ ion and $1\times 10^{-4}M$ of $NO_2^-$ ion.

The concentration of $H^+$ ion is $1\times 10^{-4}M$

First we have to calculate the pH.

$pH=-\log [H^+]$

$pH=-\log (1.0\times 10^{-4})$

$pH=4$

Now we have to calculate the pOH.

$pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-4=10$

Now we have to calculate the $OH^-$ concentration.

$pOH=-\log [OH^-]$

$10=-\log [OH^-]$

$[OH^-]=1.0\times 10^{-10}M$

Thus, the $OH^-$ concentration is, $1.0\times 10^{-10}M$

From this we conclude that, a solution of 0.10 M NaOH possess the greatest concentration of hydroxide ions.

Hence, the correct option is (d)

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3 years ago

Which type of radioactive decay can pass through the body? A.alpha emission B.beta emission C.positron emission D.gamma rays

TEA [102]

A beta emission radioactive decay can pass through the body.

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3 years ago

When the compound BaCl2 forms , what happens to the Ba and Cl ions

Korvikt [17]

Ba stays as Ba+2 and Cl stays as Cl-

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2 years ago

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