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3 years ago

An alpha particle is equivalent to a _____ nucleus.

Chemistry

2 answers:

EleoNora [17]3 years ago

7 0

Answer: B. helium

Explanation:

Alpha decay: In this process, alpha particles is emitted when a heavier nuclei decays into lighter nuclei. The alpha particle released has a charge of +2 units.

General representation of an element is given as: $_Z^A\textrm{X}$ where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}+_2^4\alpha$

As the alpha particle has atomic number of 2 and mass number of 4, this is helium nuclei.

astra-53 [7]3 years ago

6 0

Alpha particle is equivalent to B. Helium atom (2 protons, 2 neutrons)

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What happens to the actin and myosin during a muscle contraction

siniylev [52]

Answer:

actin and myosin are examples of the motile protein, meaning it allows the cells and cellular activities to move around.

Explanation:

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2 years ago

Consider the reaction: P4 + 6Cl2 = 4PCl3.

likoan [24]

Answer:

The answer to your question is below

Explanation:

Consider the reaction: P4 + 6Cl2 = 4PCl3.

a. How many grams of Cl2 are needed to react with 20.00 g of P4? ___68.7 g___________

P4 + 6Cl2 = 4PCl3

4(31) ---------- 12(35.5)

20 ---------- x

x = 20(12x35.5) / 4(31)

x = 8520 / 124

x = 68.7 g

b. You have 15.00 g. of P4 and 22.00 g. of Cl2, identify the limiting reactant and calculate the grams of PCl3 that can be produced as well as the grams of excess reactant remaining. LR____________ grams PCl3 _________ grams excess reactant ___________

P4 + 6Cl2 = 4PCl3

124g 426 g 4(31 + 3(35.5)) = 550g

15g 22g

I will use P4 to find the limiting reactant

x = (15 x 426) / 124 = 51.5 The limiting reactant is Chlorine

because we need 51.5 g and we only have 22g

Excess reactant

x = (22 x 124) / 426 = 6.4 g of P4

Excess P4 = 15 g - 6.4 = 8.6 g of P4 in excess

Grams of PCl3 produced

426 g of Cl2 ---------------- 550 g of PCl3

22g of Cl2 ------------- - x

x = (22 x 550) / 426 = 28.4 g of PCl3

c. If the actual amount of PCl3 recovered is 16.25 g., what is the percent yield? ______________

% yield = (16.25 - 28.4) / 28.4 x 100

% yield = 42.8

d. Given 28.00 g. of P4 and 106.30 g. of Cl2, identify the limiting reactant and calculate how many grams of the excess reactant will remain after the reaction. LR ______________ grams excess reactant

Limiting reactant

124g of P4 ------------- 426 g 6Cl2

28g --------------- x

x = (28 x 426) / 124

x = 96.2 g of Cl2 and we have 106.3 so Chlorine is the excess reactant and P4 is the limiting reactant.

Excess reactant = 106.3 - 96.2 = 10.1 g of Cl2 in excess

4 0

2 years ago

B. if 6.73 g of na2co3 is dissolved in enough water to make 250. ml of solution, what is the molar concentration of sodium carbo

BARSIC [14]

Answer:- $[Na_2CO_3]=0.254M$ , $[Na^+]=0.508 M$ , $[CO_3^2^-]=0.254M$

Solution:- We are asked to calculate the molarity of sodium carbonate solution as well as the sodium and carbonate ions.

Molarity is moles of solute per liter of solution. We have been given with 6.73 grams of sodium carbonate and the volume of solution is 250.mL. Grams are converted to moles and mL are converted to L and finally the moles are divided by liters to get the molarity of sodium carbonate.

Molar mass of sodium carbonate is 105.99 gram per mol. The calculations for the molarity of sodium carbonate are shown below:

$\frac{6.73gNa_2CO_3}{250.mL}(\frac{1mol}{105.99g})(\frac{1000mL}{1L})$

= $0.254MNa_2CO_3$

So, molarity of sodium carbonate solution is 0.254 M.

sodium carbonate dissociate to give the ions as:

$Na_2CO_3(aq)\rightarrow 2Na^+(aq)+CO_3^2^-$

There is 1:2 mol ratio between sodium carbonate and sodium ion. So, the molarity of sodium ion will be two times of sodium carbonate molarity.

$[Na^+]=2(0.254M)$ = 0.508 M

There is 1:1 mol ratio between sodium carbonate and carbonate ion. So, the molarity of carbonate ion will be equal to the molarity of sodium carbonate.

$[CO_3^2^-]=0.254M$

5 0

3 years ago

What error, if any, would the calculated density of the solid have if the material had a hollow center?

maria [59]

Answer:

3) The calculated density would be high, because the volume would be incorrectly measured low.

Explanation:

Density is defined as mass per unit volume. It means the density is inversely proportional to the volume.

A solid with a hollow center will have high volume due to air inside the hollow area that will lead to low density.

But the error in the calculation of density is that the "density would be high, because the volume would be incorrectly measured low."

Hence, the correct answer is "3)"

3 0

2 years ago

What does it mean when a reaction is spontaneous apex?

natima [27]

A reaction that is spontaneous means that it can produce products without the supply of energy. The total energy from the reactants reached the activation energy that allow the reaction proceed. An example of this is the decay of a diamond into graphite occuring readily.

7 0

3 years ago