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3 years ago

Why does an ice cube melt when you hold it in your hand?

Chemistry

2 answers:

Sloan [31]3 years ago

4 0

Answer:

Your hand transports heat.

Explanation:

Your hand gives the heat from your skin to the cube which makes your hand cold. It is NOT the cold ice penetrating the skin. This is why the cube melts.

sesenic [268]3 years ago

3 0

Heat
ANYWYAS PLA HELP

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What’s the correct answer

Fed [463]

The correct answer is:
_________________________________________________________
" F and Br , because they are in the same group" .
_________________________________________________________
Note:
_________________________________________________________
Choice [B]: "F and Br ; because they are in the same period" ; is incorrect; since "F" and "Br" are not in the same "period" (that is, "row").
______________________________________________________
Choice [C]: "Na and Mg; because they are in the same group {"column"} ; is incorrect; since: "Na" and "Mg are NOT in the same group {"column"].
_______________________________________________________
Choice [D]: "Na and Mg" ; because they are in the same period {"row"}; is incorrect. Note: "Na" and "Mg" are, in fact, in the same period {"row"}. However, as aforementioned, {Mg and Na} are not in the same group {"column".}.

Note: The similiarities in physical and chemistry properties among elements are determined and organized — or tend to be so—by "groups" {"columns"} — NOT by "periods" {rows}.
______________________________________________________

3 0

4 years ago

What would be the composition and ph of an ideal buffer prepared from lactic acid (ch3chohco2h), where the hydrogen atom highlig

Mashutka [201]

Answer:

$P_H =2.86$

$c=1.4\times 10^{-4}$

Explanation:

first write the equilibrium equaion ,

$C_3H_6O_3$ ⇄ $C_3H_5O_3^{-} +H^{+}$

assuming degree of dissociation $\alpha$ =1/10;

and initial concentraion of $C_3H_6O_3$ =c;

At equlibrium ;

concentration of $C_3H_6O_3 = c-c\alpha$

$[C_3H_5O_3^{-} ]= c\alpha$

$[H^{+}] = c\alpha$

$K_a = \frac{c\alpha \times c\alpha}{c-c\alpha}$

$\alpha$ is very small so $1-\alpha$ can be neglected

and equation is;

$K_a = {c\alpha \times \alpha}$

$[H^{+}] = c\alpha$ = $\frac{K_a}{\alpha}$

$P_H =- log[H^{+} ]$

$P_H =-logK_a + log\alpha$

$K_a =1.38\times10^{-4}$

$\alpha = \frac{1}{10}$

$P_H= 3.86-1$

$P_H =2.86$

composiion ;

$c=\frac{1}{\alpha} \times [H^{+}]$

$[H^{+}] =antilog(-P_H)$

$[H^{+} ] =0.0014$

$c=0.0014\times \frac{1}{10}$

$c=1.4\times 10^{-4}$

6 0

4 years ago

Question 107 points)

____ [38]

Answer:

Evaporation from the hydrosphere provides the medium for cloud and rain formation in the atmosphere. The atmosphere brings back rainwater to the hydrosphere. The atmosphere provides the geosphere with heat and energy needed for rock breakdown and erosion. The geosphere, in turn, reflects the sun's energy back into the atmosphere.

Explanation:

4 0

3 years ago

1. How many moles are contained in 2.22 x 1024 molecules of calcium fluoride?

Black_prince [1.1K]

Answer:

= 3.7moles

Explanation:

I mole = 6.022 × 10²³ molecules

I molecule = 1 ➗ 6.022 × 10²³ moles

2.22 ×10‘’ 24molecules = (2.22×10‘’ 24) ÷6.022 × 10²³ moles

Number of moles = 2.22/6.022 × 10" 24-23

Number of moles = 0.37 × 10

Number of moles = 3.7moles

I hope this was helpful, please mark as brainliest

3 0

3 years ago

The element silver exists in nature as two isotopes: 107Ag has a mass of 106.9051 u, and 109Ag has a mass of 108.9048 u. The ave

Lilit [14]

Answer:

107Ag has abundance of 51.7%

109Ag has abundance of 48.3%

Explanation: Please see attachment for explanation

3 0

3 years ago