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2 years ago

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What is true about the elements of a period? They have the same number of electron shells. They have similar chemical characteri

stics. They have similar physical characteristics. They transition from a metal to nonmetal to inert gas from left to right.

2 answers:

Klio2033 [76]2 years ago

4 0

Answer:

They have the <u>same number of electron shells,</u> and <u>they transition from a metal to nonmetal to inert gas from left to right.</u>

cricket20 [7]2 years ago

3 0

The first and the last statement are correct

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Use the picture to answer the following questions.

vesna_86 [32]

1. the producer is the wheat/plant (producers create their own energy, example is photosynthesis in plants)
2. the consumer is the bird (hint all consumers have mouths. they have to eat/ drink something to produce energy)

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2 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

3 years ago

Copper(II) sulfate pentahydrate, CuSO4 ·5 H2O, (molar mass 250 g/mol) can be dehydrated by repeated heating in a crucible. Which

prohojiy [21]

Answer:

The water lost is 36% of the total mass of the hydrate

Explanation:

<u>Step 1:</u> Data given

Molar mass of CuSO4*5H2O = 250 g/mol

Molar mass of CuSO4 = 160 g/mol

<u>Step 2:</u> Calculate mass of water lost

Mass of water lost = 250 - 160 = 90 grams

<u>Step 3:</u> Calculate % water

% water = (mass water / total mass of hydrate)*100 %

% water = (90 grams / 250 grams )*100% = 36 %

We can control this by the following equation

The hydrate has 5 moles of H2O

5*18. = 90 grams

(90/250)*100% = 36%

(160/250)*100% = 64 %

The water lost is 36% of the total mass of the hydrate

8 0

2 years ago

What do melted ice cooling lava and boiling water have in common?

KIM [24]

They are all transioning in states of matter

7 0

3 years ago

When 1 mol of KBr(s) decomposes to its elements, 394 kJ of heat is absorbed. (a) Write a balanced thermochemical equation.

VladimirAG [237]

The balanced thermochemical equation is

KBr ------- K + 1/2 Br2

<h3>What is thermochemical equation? </h3>

A Thermochemical Equation is defined as the balanced stoichiometric chemical equation which includes the enthalpy change, ΔH.

The chemical equation for the decomposition of potassium bromide to its constituent elements bromine ans potassium :

KBr ----- K + Br2

The balanced thermochemical equation of the decomposition of potassium bromide to its constituent elements potassium and bromide as follows

KBr ------- K + 1/2 Br2

As the heat is absorbed in this reaction therefore, heat is positive.

Thus, we concluded that the balanced thermochemical equation is

KBr ------- K + 1/2 Br2

learn more about thermochemical equation:

brainly.com/question/2733624

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8 0

1 year ago