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2 years ago

Which option is an example of a physical property?

Chemistry

2 answers:

Flura [38]2 years ago

5 0

Answer:

i took the test on k12 so hope this helps

iren [92.7K]2 years ago

4 0

Answer:

Explanation:

the tendency of a material to conduct heat or electricity can be detected on the outside

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A ray of yellow light has a wavelength of about 5.8×10−7 m. Will exposure to yellow light cause electrons to be emitted from ces

Dima020 [189]

Given the wavelength of the yellow light (700 nm. in this case) we can find the frequency
by dividing the speed of light c by the wavelength w, that is: f = c/w and we know that 
c is equal to 2.998 * 10**8 meters per second. 
So the frequency f = (2.998 * 10**8) / (7.0 * 10**-7) = 4.283 * 10**14 cycles per sec. 
(or Hz.) Since the threshold frequency of Cs is 9.39 * 10**14 Hz, the red light doesn't 
have a high enough frequency (or energy) to cause electron emission. 
Hope this answers your question.

8 0

3 years ago

Why electronegative decrease going down the periodic table

liraira [26]

Moving down in a group, the electronegativity decreases due to an increase in the distance between the nucleus and the valence electron shell, thereby decreasing the attraction, making the atom have less of an attraction for electrons or protons.

5 0

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 :

(a) a solution of pH 3.0

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, $1.0\times 10^{-11}M$

(b) a solution of 0.10 M $NH_3$

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

(c) a solution with a pOH of 12.

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, $1.0\times 10^{-12}M$

(d) a solution of 0.10 M NaOH

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

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

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)

3 0

3 years ago

When the molecules of gases are heated, the average kinetic energy of the molecules increases,

serious [3.7K]

True is the answer to this

6 0

3 years ago

Flourine is found to undergo 10% radioactivity decay in 366 minutes determine its halflife

yuradex [85]

Answer:

$\boxed{\text{2408 min}}$

Explanation:

The integrated rate law for radioactive decay is

$\ln\dfrac{N_{0}}{N_{t}} = kt$

1. Calculate the decay constant

$\begin{array}{rcl}\ln \dfrac{100}{90} & = & k \times 366\\\\1.054 & = & 366k\\\\k & = & \dfrac{1.054 }{366}\\\\k & = & 2.879 \times 10^{-4} \text{ min}^{-1}\\\end{array}\\\\$

2. Calculate the half-life

$t_{\frac{1}{2}} = \dfrac{\ln2}{k}\\\\t_{\frac{1}{2}} = \dfrac{\ln2}{2.879 \times 10^{-4} \text{ min}^{-1}} = \text{2408 min}\\\\\text{The half-life for decay is } \boxed{\textbf{2408 min}}$

8 0

3 years ago