Determine the half-life of potassium if in 3460 years a 200 g sample decayed into 25 g

Answers

Answer 1

Answer: $M=m_o*(1)/(2)^(t)/(T)\n M-mass\ aftter\ decay\n m-initial\ mass\n t-time\n T-period(half-life)\n 25=200*(1)/(2)^(3460)/(T)|:200\n (1)/(8)=((1)/(2))^(3460)/(T)\n ((1)/(2))^3=((1)/(2))^(3460)/(T)\n 3=(3460)/(T)\n T=1153(1)/(3)$

or easiest way
200g -----> 100g -------> 50g -----> 25g
We can that there were three decays.
1 decay ----------- x years
3 decays---------- 3460
$x=1153(1)/(3)$

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Electronegativities of the elements Na, Al, P, and Cl follow a specific trend across the period. Based on this trend, an electron will be most strongly attracted toNa.
Al.
P.
Cl.

Answers

Based on the trend, an electron will be most strongly attracted to Cl, chlorine. The correct option is D.

What is electronegativity?

Electronegativity is a property of an element which show the tendency of that element to accept electrons from other element. When an atom accept electrons, it gets a negative charge, the charge increase with the increase of accepting number of electrons.

Chlorine is a gas and is highly acidic. It has the highest electronegativity because it has the highest tendency to form a covalent bond with other element.

Chlorine has seven electrons in its outer shell, and it needs only one electron to complete its octave equal to the noble gas configuration.

Thus, the correct option is D. Cl.

To learn more about electronegativity, refer to the link:

brainly.com/question/17762711

#SPJ6

Answer:

Explanation:

The electronegativity follow the trend that the higher the element is the more electronegative he is, for exemplo, in F, Cl and Br are all from the same group, 17A, put F has the lowest atomic number, followed by Cl and Br is the last, because of that F is the more electronegative from them, followed for Cl and Br is the element with lowest electronegativity.

And this trend also says that the element that are on the right of the table will have the higher electronegativity, for exemplo F, K and Be, all of the will have electron on the second band of valence but F is for the group 17A, K is from the 1A and Be is form the 2A. Because of that F is, one again, the one with the highest electronegativity followed by Be and K is the one with the lowest electronegativity of them all.

Where is the smallest negatively-charged particle found in an atom?

Answers

Answer:

In the orbitals of the atom

Which monosaccharide commonly found in all disaccharides?

Answers

galactose its formed when itis joined together

glucose is found in all disaccharides.Two glucose form maltose;glucose +fructose =sucrose and glucose + galactose= lactose.

Show the calculation of the molar mass (molecular weight) of a solute if a solution of 5.8 grams of the solute in 100 grams of water has a freezing point of 1.20oC. Kf for water is 1.86

Answers

Answer : The molar mass of solute is, 89.9 g/mol

Explanation : Given,

Mass of solute = 5.8 g

Mass of solvent (water) = 100 g

Formula used :

$\Delta T_f=K_f* m\n\nT_f^o-T_f=T_f*\frac{\text{Mass of solute}* 1000}{\text{Molar mass of solute}* \text{Mass of water}}$

where,

$\Delta T_f$ = change in freezing point

$T_f^o$ = temperature of pure solvent (water) = $0^oC$

$T_f$ = temperature of solution = $1.20^oC$

$K_f$ = freezing point constant of water = $1.86^oC/m$

m = molality

Now put all the given values in this formula, we get

$(0^oC)-(1.20^oC)=1.86^oC/m* \frac{5.8g* 1000}{\text{Molar mass of solute}* 100g}$

$\text{Molar mass of solute}=89.9g/mol$

Therefore, the molar mass of solute is, 89.9 g/mol

A transformer has a primary voltage of 115 V and a secondary voltage of 24 V. If the number of turns in the primary is 345, how many turns are in the secondary? A. 1,653
B. 690
C. 72
D. 8

Answers

There are numerous information's of immense importance already given in the question.
Primary voltage of the transformer (V1) = 115 V
Secondary voltage of the transformer (V2) = 24 V
Number of turns in the primary (T1) = 345
Let us assume the number of turns in the secondary = T2
Then
(V1/V2) = (T1/T2)
(115/24) = 345/T2
115T2 = 345 * 24
115 T2 = 8280
T2 = 8280/115
= 72
So the correct option among all the options given in the question is option "C".

Answer:

The is 1653

Explanation:

Primary Voltage = # of turns in primary

Secondary Voltage # of turns in secondary

115 V = 345

24 V # of turns in secondary

115\25=4.79167

4.79167 = 345

# of turns in secondary

4.79167 * 345 = 1653.12

When rounded 1653

Which statement best describes the conductivity of weak electrolytes, such as weak acids and bases?A) Weak electrolytes do not dissolve in water and can not conduct electricity.
B) Weak electrolytes dissolve and partially dissociate in water providing charged ions to conduct electricity.
C) Weak electrolytes dissolve and completely dissociate in water providing charged ions to conduct electricity.
D) Weak electrolytes dissolve and does not dissociate in water providing no charged ions to conduct electricity.

Answers

Answer: B) Weak electrolytes dissolve and partially dissociate in water providing charged ions to conduct electricity.

Explanation: Weak electrolytes are those substances which do not dissociate completely when dissolved in water. They dissociate but then associate back and thus their dissociation is shown by an equilibrium sign. Example: $CH_3COOH$

$CH_3COOH\rightarrow CH_3COO^-+H^+$

The charged species formed helps in the conduction of electricity.

Strong electrolytes are those substances which dissociate completely when dissolved in water. Their dissociation is shown by a forward arrow. Example: $NaOH$

$NaOH\rightarrow Na^++OH^-$

The charged species formed helps in the conduction of electricity.

B. Weak electrolytes are weak because they only partially dissociate into ions in water.

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