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2 years ago

A certain element has 52 protons, 52 electrons, and 76 neutrons. its atomic mass is _____. 52 76 128 104

Chemistry

2 answers:

kifflom [539]2 years ago

5 0

Pretty sure it is 128 hope this helps you :D

Nikitich [7]2 years ago

4 0

Answer:

Atomic mass is 128

Explanation:

Atoms are composed of fundamental subatomic particles: protons, neutrons and electrons.

They are represented by a standard nuclear notation which includes the symbol of the element, its atomic number and atomic mass.

i.e. $_{Z}^{A}\textrm{X}$

Z = atomic mass = number of protons + number of neutrons -----(1)

A = atomic number = number of protons = number of electrons----(2)

Given data:

Protons = 52

Electrons = 52

Neutrons = 76

Based on equation (1)

Atomic mass = 52 + 76 = 128

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Calculate the area of a 3.0 inch by 5.0 inch index card in square millimeters (mm). (You can look up the formula for the area of

meriva

Answer:

The area of the given rectangular index card = 9677.4 mm²

Explanation:

Area is defined as the space occupied by a two dimensional shape or object. The SI unit of area is square metre (m²).

The area of a rectangle (A) = length (l) × width (w)

Given dimensions of the rectangle: Length (l) = 5.0 inch, Width (w) = 3.0 inch

Since, 1 inch = 25.4 millimetres (mm)

Therefore, l = 5 × 25.4 = 127 mm, and w = 3 × 25.4 = 76.2 mm

Therefore, the area of the given rectangular index card = A= l × w = 127 mm × 76.2 mm = 9677.4 mm²

5 0

2 years ago

defon

1) Calcium carbonate contains 40.0% calcium by weight.
M(CaCO₃)=100.1 g/mol
M(Ca)=40.1 g/mol
w(Ca)=40.1/100.1=0.400 (40.0%)!

2) Mass fraction of this is excessive data.

3) The solution is:

m(Ca)=1.2 g

m(CaCO₃)=M(CaCO₃)*m(Ca)/M(Ca)

m(CaCO₃)=100.1g/mol*1.2g/40.1g/mol=3.0 g

4 0

2 years ago

Read 2 more answers

If the molar absorptivity constant for the red dye solution is 5.56×104 M-1cm-1, calculate the molarity of the red dye solution

Shtirlitz [24]

Explanation:

a) Using Beer-Lambert's law :

Formula used :

$A=\epsilon \times c\times l$

where,

A = absorbance of solution = 0.945

c = concentration of solution = ?

l = length of the cell = 1.20 cm

$\epsilon$ = molar absorptivity of this solution = $5.56\times 10^4 M^{-1} cm^{-1}$

$0.945=5.56\times 10^4 M^{-1} cm^{-1}\times 1.20 \times c$

$c=1.4163\times 10^{-5} M=14.16 \mu M$

( $1\mu M=10^{-6} M$ )

14.16 μM is the molarity of the red dye solution at the optimal wavelength 519nm and absorbance value 0.945.

b) $c=1.4163\times 10^{-5} mol/L$

1 L of solution contains $1.4163\times 10^{-5}$ moles of red dye.

Mass of $1.4163\times 10^{-5}$ moles of red dye:

$1.4163\times 10^{-5}\times 879.86g/mol=0.01246 g$

$(w/v)\%=\frac{\text{Mass of solute (g)}}{\text{Volume of solvent (mL)}}\times 100$

$red(w/v)\%=\frac{0.01246 g}{1000 mL}\times 100=0.001246\%$

c) In order to dilute red dye solution by 5 times, we will need to add 1 L of water to solution of given concentration.

Concentration of red dye solution = $c=1.4163\times 10^{-5} M$

Concentration of red solution after dilution = c'

$c=c'\times 5$

$1.4163\times 10^{-5} M=c'\times 5$

$c'=2.83\times 10^{-6} M$

The final concentration of the diluted solution is $2.83\times 10^{-6} M$

8 0

3 years ago

Mercury (Hg) poisoning is a debilitating disease that is often fatal. In the human body, mercury reacts with essential enzymes l

alisha [4.7K]

Answer:

6 x 10⁵ kg Hg

Explanation:

The mass of mercury in the entire lake is found by multiplying the concentration of the mercury by the volume of the lake.

The volume of the lake is calculated in cubic feet:

V = (SA)x(depth) = (100mi²)(5280ft/mi)² x (20ft) = 5.57568 x 10¹⁰ ft³

Cubic feet are then converted to mL (1cm³=1mL)

(5.57568 x 10¹⁰ ft³) x (12in/ft)³ x (2.54cm/in)³ = 1.578856752 x 10¹⁵ mL

The mass of mercury is then found:

m = CV = (0.4μg/mL)(1g/10⁶μg)(1kg/1000g) x (1.578856752 x 10¹⁵ mL) = 6 x 10⁵ kg Hg

3 0

2 years ago

HIII PLEASE HELP BRUUH

leonid [27]

1. 2Al(s)+6HCl(aq)⇒2AlCl₃(aq)+3H₂(g)

2. 2AgNO₃ (aq) + Cu (s)⇒Cu(NO₃)₂ (aq) + 2Ag (s)

3. 2C₃H₈O(l) + 9O₂(g) ⇒ 6CO₂(g) + 8H₂O(g)

<h3>Further explanation</h3>

There are several reactions that can occur in a chemical reaction: single replacement, double replacement, synthesis, decomposition or combustion, etc.

1.Al(s)+HCl(aq)⇒AlCl₃(aq)+H₂(g)

type : single replacement

balance :

2Al(s)+6HCl(aq)⇒2AlCl₃(aq)+3H₂(g)

2. AgNO₃ (aq) + Cu (s) ⇒ Cu(NO₃)₂ (aq) + Ag (s)

type : single replacement

balance :

2AgNO₃ (aq) + Cu (s)⇒Cu(NO₃)₂ (aq) + 2Ag (s)

3. C₃H₈O + O₂ ⇒ CO₂ + H₂O

type : combustion of alcohol

balance :

2C₃H₈O(l) + 9O₂(g) ⇒ 6CO₂(g) + 8H₂O(g)

4 0

2 years ago