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vesna_86 [32]
3 years ago
5

An atom of Calcium has 2 valence electrons and an atom of sulfur has 6 valence electrons. How many lone pairs of electrons are p

resent in the Lewis structure of Calcium Sulfide? one two three four none
Chemistry
1 answer:
Anarel [89]3 years ago
7 0
The answer is 2. this is what it would look like 

:Ca = S: 

 Hope this helps 
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The pressure on 30 milliliters of an ideal gas increases from
Nana76 [90]

V1 = 30 mL

P1 = 760 torr

P2 = 1520 torr

V2 = ?

applying Boyle's Law

P1*V1 = P2*V2

760 torr * 30 mL = 1520 torr * V2

V2 = 760 torr * 30 mL / 1520 torr

( C ) is correct

8 0
3 years ago
A 0.1 mm sample of human blood has approximately 6000 red blood cells. An adult typically has 5.0 L of blood. How many red blood
olga55 [171]

 3.0 × 10¹¹ RBC's    (or)      3E11 RBC's


Solution:

Step 1: Convert mm³ into L;


As,


                                            1 mm³  =  1.0 × 10⁻⁶ Liters


So,


                                         0.1 mm³  =  X  Liters


Solving for X,


                       X  =  (0.1 mm³ × 1.0 × 10⁻⁶ Liters) ÷ 1 mm³


                       X  =  1.0 × 10⁻⁷ Liters


Step 2: Calculate No. of RBC's in 5 Liter Blood:


As given


                        1.0 × 10⁻⁷ Liters Blood contains  =  6000 RBC's


So,


                         5.0 Liters of Blood will contain  =  X  RBC's


Solving for X,


                      X  =  (5.0 Liters × 6000 RBC's) ÷ 1.0 × 10⁻⁷ Liters


                      X  =  3.0 × 10¹¹ RBC's


Or,


                     X  =  3E11 RBC's



5 0
3 years ago
It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry
Fittoniya [83]

Answer:

a) Pf = 689.4 bar

b) P = 226.6 bar

c) T = 269.99 K

Explanation:

a)

The molar volume of ice is equal to:

Vi = m/p = (18.02x10^-3 kg H2O/1 mol H2O)*(1 m^3/920 kg) = 1.96x10^-5 m^3 mol^-1

The molar volume of liquid water is equal to:

Vl = (18.02x10^-3 kg/1 mol)*(1 m^3/997 kg) = 1.8x10^-5 m^3 mol^-1

The change in volume is equal to:

ΔVchange = Vi-Vl = 1.96x10^-5 - 1.8x10^-5 = 1.5x10^-6 m^3 mol^-1

using the Clapeyron equation:

Pf = Pi + ((ΔHf*ΔT)/(ΔVf*Ti)) = 1.013x10^5 Pa + ((6010 J mol^-1 * 4.7 K)/(1.5x10^-6 * 273.15 K)) = 6.89x10^7 Pa = 689.4 bar

b)

For the pressure we will use the equation:

P = (m*g)/A, where m is the mass, g is the acceleration of gravity and A is the area. Replacing values:

P = (79 kg * 9.81 m s^-2)/(1.9x10^-4 m * 0.18 m) = 2.26x10^7 Pa = 226.6 bar

c)

From Clapeyron´s expression we need to clear ΔT:

ΔT = ((Pf-Pi)*ΔV*Ti)/ΔHf = ((2.26x10^7 - 6.89x10^7)*1.5x10^-6*273.15)/6010 = -3.16 K

you can evaluate the new melting point of ice:

T = Ti + ΔT = 273.15 K - 3.16 K = 269.99 K

4 0
3 years ago
The characteristic functional groups of a protein are _____.
V125BC [204]

Answer:

\boxed{\text{amide groups}}

Explanation:

A protein is a long chain of amino acids linked together by amide groups.

The general structure is

\rm \left[-NHCHR-\underbrace{\hbox{CO-NH}}_{\hbox{amide group}}-CHRCO-\right]_{n}

4 0
3 years ago
What would be the expected radius of a nucleus having 82 protons and 125 neutrons?
Luba_88 [7]

The expected radius of a nucleus having 82 protons and 125 neutrons would be 5.2 fm.

<h3>What is a nucleus in the atom?</h3>

The nuclei are incredibly tiny and dense. They are 10 thousand times smaller than an atom and have more than 99.9% of their mass. Protons, which have a positive charge, and neutrons, which have no electrical charge, make up the nucleus. Alternately, protons and neutrons make up an atom's nucleus. While neutrons have no charge but weigh the same as protons, protons have a positive charge that is equivalent to the orbiting electrons. Based on the 1909 Geiger-Marsden gold foil experiment, Ernest Rutherford identified the atomic nucleus in 1911, which is the compact, dense region made up of protons and neutrons at the heart of an atom.

To learn more about the nucleus, visit:

brainly.com/question/23366064

#SPJ4

7 0
2 years ago
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