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2 years ago

In the nucleus of an Adam there are 18 protons and 20 neutrons what are the atomic number and mass number of this isotope

Chemistry

2 answers:

yKpoI14uk [10]2 years ago

6 0

Atomic number = 18 (Number of protons)
Mass number = 18 + 20 (Number of protons + neutrons)

abruzzese [7]2 years ago

3 0

Answer:

The atomic number this isotope is 18.

The atomic mass this isotope is 38.

Explanation:

Atomic number(Z) = Total numbers of protons

Mass number (A) = Total number of protons(Z) + Total number of neutrons(N)

A = Z + N

We have :

Number of protons in a nucleus of a given atom of an isotope, Z= 18

Number of neutrons in a nucleus of a given atom of an isotope, N= 20

A = Z + N = 18 + 20 = 38

The atomic number this isotope is 18.

The mass number this isotope is 38.

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A solution is made by adding 29.1 mL of concentrated perchloric acid ( 70.5 wt% , density 1.67 g/mL ) to some water in a volumet

Lera25 [3.4K]

Answer:

The concentration of the solution is 1.364 molar.

Explanation:

Volume of perchloric acid = 29.1 mL

Mass of the solution = m

Density of the solution = 1.67 g/mL

$m=1.67 g/mL\times 29.1 mL=48.597 g$

Percentage of perchloric acid in 48.597 solution :70.5 %

Mass of perchloric acid in 48.597 solution :

= $\frac{70.5}{100}\times 48.597 = 34.261 g$

Moles of perchloric acid = $\frac{34.261 g}{100.46 g/mol}=0.3410 mol$

In 29.1 mL of solution water is added and volume was changed to 250 mL.

So, volume of the final solution = 250 mL = 0.250 L (1 mL = 0.001 L)

$Molarity=\frac{Moles}{Volume (L)}$

$=\frac{0.3410 mol}{0.250 L}=1.364 M$

The concentration of the solution is 1.364 molar.

6 0

2 years ago

A student performs an experiment similar to what you will be doing in lab, except using titanium metal instead of magnesium meta

Genrish500 [490]

Answer:

n = 0.0022 mol

Explanation:

Moles is denoted by given mass divided by the molar mass ,

Hence ,

n = w / m

n = moles ,

w = given mass ,

m = molar mass .

From the information of the question ,

w = 0.108 g

As we known ,

The molar mass of titanium = 47.867 g / mol

The mole of titanium can be caused by using the above relation , i.e. ,

n = w / m

n = 0.108 g / 47.867 g / mol

n = 0.0022 mol

7 0

3 years ago

Osmotic pressure Π is given by the relation:Π = iMRTwhere i is the van’t Hoff factor, M is the concentration of solute, R is the

lions [1.4K]

<u>Answer:</u> The concentration of solute is 0.503 mol/L

<u>Explanation:</u>

To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

$\pi=icRT$

where,

$\pi$ = osmotic pressure of the solution = 24 atm

i = Van't hoff factor = 2 (for NaCl)

c = concentration of solute = ?

R = Gas constant = $0.08\text{ L atm }mol^{-1}K^{-1}$

T = temperature of the solution = $25^oC=[273+25]=298K$

Putting values in above equation, we get:

$24atm=2\times c\times 0.08\text{ L.atm }mol^{-1}K^{-1}\times 298K\\\\c=0.503mol/L$

Hence, the concentration of solute is 0.503 mol/L

5 0

2 years ago

BRAINLIESTTT ASAP!!! PLEASE HELP ME. :)

dolphi86 [110]

Answer:

Mechanical Energy = A

Gravitational Energy = C

Nuclear Energy = B

Thermal Energy = D

Explanation:

Hope this helps you :) If any are wrong, I'm very sorry.

8 0

3 years ago

Read 2 more answers

Magnesium metal burns in air to form a mixture of magnesium oxide (MgO, M = 40.31) and magnesium nitride (Mg3N2, M = 100.95). A

dedylja [7]

Answer:

26.95 %

Explanation:

Air contains the highest percentage of oxygen and nitrogen gases. Magnesium then combines with both of the gases:

$2 Mg (s) + O_2 (g)\rightarrow 2 MgO (s)$

$3 Mg (s) + N_2 (g)\rightarrow Mg_3N_2 (s)$

Firstly, find the total number of moles of magnesium metal:

$n_{Mg} = \frac{1.000 g}{24.305 g/mol} = 0.041144 mol$

Let's say that x mol react in the first reaction and y mol react in the second reaction. This means:

$x + y = 0.041144 mol$

According to stoichiometry, we form:

$n_{MgO} = x mol, n_{Mg_3N_2} = \frac{y}{3} mol$

Multiplying moles by the molar mass of each substance will yield mass. This means we form a total of:

$m_{MgO} = 40.31x g, m_{Mg_3N_2} = \frac{y}{3} 100.95 g =$

The total mass is given, so we have our second equation to solve:

$40.31x + 33.65y = 1.584$

We have two unknowns and two equations, we may then solve:

$x + y = 0.041144$

$40.31x + 33.65y = 1.584$

Express y from the first equation:

$y = 0.041144 - x$

Substitute into the second equation:

$40.31x + 33.65(0.04144 - x) = 1.584$

$40.31x + 1.39446 - 33.65x = 1.584$

$6.66x = 0.18954$

$x = 0.028459$

$y = 0.041144 - x = 0.012685$

Moles of nitride formed:

$n_{Mg_3N_2} = \frac{y}{3} = 0.0042282 mol$

Convert this to mass:

$m_{Mg_3N_2} = 0.0042282 mol\cdot 100.95 g/mol = 0.4268 g$

Find the percentage:

$\omega_{Mg_3N_2} = \frac{0.4268 g}{1.584 g}\cdot 100\% = 26.95 \%$

7 0

2 years ago