In a molecule of calcium sulfide, calcium has two valence electron bonds, and a sulfur atom has six valence electrons. How many lone pairs of electrons are present in the Lewis structure of calcium sulfide? Also, state why.
A. one
B. two
C. three
D. four
E. none
There are 2 lone pairs
Further explanationGiven
a molecule of calcium sulfide
two valence electron of Calcium(Ca)
six valence electrons of Sulfur(S)
Required
number of lone pairs of electrons
Solution
Lewis structure shows the form of bonds that occur in the valence electrons of an element or compound
Valence electrons are electrons used in a chemical bond
To achieve stability, the element S needs 2 more electrons which are obtained from 2 electrons from the Ca element,
A lone pair electrons means refers to an unshared pair of electrons(not bonding to the other atoms)
A gymnast performing a backflip into a cartwheel on a balance beam is am example of ________ force
what is the net force of 4N 2N!!
Answer: 4 N-2 N=2 Nto the left. Change in motion: The box will move to the left. 7.)
Explanation: Please mark branliest.
what causes a change in air pressure
Could you use filtration on a solution?
Answer:
No.
Explanation:
This is because a solution is a mixture with two substances that have already dissolved in each other and so there is no residue left. Filtration works such that part of the mixture has smaller particles that can pass through the membrane of the filter paper while the bigger particles get stuck onto the paper as residue. A solution has a uniform size particle throughout and thus filtration does not work for purifying a solution.
ill attach a picture
Answer:
35.50
Explanation:
There are two stable isotopes, 35Cl (75.77%) and 37Cl (24.23%), giving chlorine a standard atomic weight of 35.45
What does eggshells change color under the influence of various liquids?
Answer:Adding calcium to chicken's food is going to make the eggshells firmer. Independent variable:
Explanation:
A heat energy of 645 J is applied to a sample of glass with a mass of 28.4 g. Its temperature increases from –11.6 °C to 15.5 °C. Calculate the specific heat of glass.
Answer:838J/kg/K
Explanation:
use : Q= mS◇ T
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The Earth's _____ provides protection from meteorite impacts by causing them to _____.
please leave a simple answer
Answer:
atmosphere, break up
Explanation:
Answer:
Atmosphere, break up
Explanation:
Which statement is true about a reaction represented by a chemical equation that shows energy as a reactant?

A.
It absorbs energy.

B.
It releases energy.

C.
It is a replacement reaction.

D.
It is a combustion reaction.
How does dermal tissue play a key role in transpiration?
Answer:
Dermal tissue of the stems and leaves is covered by a waxy cuticle that prevents evaporative water loss. Stomata are specialized pores that allow gas exchange through holes in the cuticle. Unlike the stem and leaves, the root epidermis is not covered by a waxy cuticle which would prevent absorption of water.
Explanation:
1. Se preparan 750 ml de una disolución en agua, que contiene 0,00071 moles de Nitrato de potasio para adobar una carne de res. Calcular la ppm de la disolución. 2. Una muestra de 600 ml de disolución tiene 4 mg de ión fluoruro (F-). Cuántas ppm de F hay en la muestra?. Ayudaaaaaa plis
Answer:
1. 95.7 ppm
2. 6.67 ppm
Explanation:
Podemos pensar la denominación ppm como partes por millón, es un tipo de unidad que define concentración de solutos en una solución.
ppm = μg/g o si lo queremos ver en volumen, μg/mL
Quiere decir microgramos de soluto en 1 g de solución o mL de solución.
Ej 1. En primer lugar convertimos los moles de KNO₃ a gramos
0.00071 mol . 101.1 g/mol = 0.071781 g
Si pasamos los gramos a μg → 0.071781 g . 1000000 μg/ 1g = 71781 μg
Dividimos 71781 μg /750 ml = 95.7 ppm
Ej 2. Convertimos los mg a μg → 4 mg . 1000 μg/ 1 mg = 4000 μg
Ahora dividimos: 4000 μg /600 ml = 6.67 ppm
7. Some products or processes claim to be "chemical free" or say "no chemicals added." Based on your understanding of chemistry, what are the arguments for and against such statements?
Please i need help
The meaning behind the statement is that the products does not contains any synthetic and harmful chemicals such as colourants, preservatives etc.
What are synthetic chemicals?All natural products or materials contains certain kind of chemicals which are naturally made in them. Such chemicals are natural chemicals and does not harm the living or causes any unwanted reaction.
The chemicals which are made by humans for specific purposes are called synthetic chemicals. Which can be of toxic and hazardous. Almost all materials we use everyday such as toothpastes, shampoo, food items, dyes, medicines and the fertilizers and pesticides we use in agriculture are all chemicals.
These chemicals helps in some way but they can be harmful to life in other way. Some products claim that they are chemical free, may true or not they intending to clear that the product does not contain any synthetic chemical except the required natural chemicals.
To find more about synthetic chemicals, refer the link below:
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25cm3 of a 0.4M sodium hydroxide solution was diluted into 250cm3 of water. What is the molarityof the resultant solution.
Answer:
0.04 M
Explanation:
From the question given above, the following data were obtained:
Initial volume of solution (V1) = 25 cm³
Initial Molarity of solution (M1) = 0.4 M
Final volume of solution (V2) = 250 cm³
Final Molarity of solution (M2) =?
We can obtain the final Molarity of the solution by using the dilution formula as illustrated below:
M1V1 = M2V2
0.4 × 25 = M2 × 250
10 = M2 × 250
Divide both side by 250
M2 = 10/250
M2 = 0.04 M
Therefore, the resulting molarity of the diluted solution is 0.04 M
what types of organisms are most likely to become extinct (characteristics)?
what method would you use for your hypothesis.
Why is it important to pasteurize certain liquids?
Answer:
Pasteurization involves heating liquids at high temperatures for short amounts of time. Pasteurization kills harmful microbes in milk without affecting the taste or nutritional value (sterilization= all bacteria are destroyed).
Explanation:
Please Answer ASAP!!
What happens to the velocity of an object when balanced forces act on it?
a.
There will be no change
c.
There will be negative acceleration
b.
There will be positive acceleration
d.
Velocity will change, but not acceleration
Please select the best answer from the choices provided
Answer:
C. There is a negative acceleration
Explanation:
I majored in Physics
will mark brainliest!
Answer:
Dilute acid + carbonate used in making the salt of copper sulfate.
Explanation:
In this experiment an insoluble metal oxide is reacted with a dilute acid to form a soluble salt.Copper(II) oxide, a black solid, and colourless dilute sulfuric acid react to produce copper(II) sulfate,giving a characteristic blue colour to the solution.
What chemical process occurs in cells to release energy?
A.
Oxidation
B.
Respiration
C.
Pespiration
D.
Nutrition
Answer:
B. Respiration
Explanation:
cellular respiration is the process where cells use glucose (C6H12O6) and oxygen gas (O2) to make carbon dioxide (CO2) water (H2O) and ATP, which is energy
formula:
C6H12O6 + 6O2 -> 6CO2 + 6H20 + 38ATP
What does the little ‘3’ in 2NH3 mean?
Answer:
It determines the number of molecules
Answer:
it means there are 3 hydrogen atoms in the compound.
In a living cell which process uses up atp
Answer:
Metabolism
Explanation:
because energy change takes place
please help !!!!!!!!!!!
Answer:
Iron wood is very dense and will sink in water. B
Explanation:
Hope this helps!!
Answer:
B
Explanation:
1. Suppose that there were two isotopes of Sodium.
28% of the naturally occurring sodium atoms had a
mass of 22, and 72% atoms had a mass of 23. What
would the average atomic weight of sodium be?
Answer: C. The university surveys 600 randomly selected students who attend the university. Correct
Explanation:
22.72 is the average atomic weight of sodium.
What are isotopes?Isotopes are different versions of a specific element.
1st isotopes of 22u = 28%
2nd isotopes of 23u = 72%
The average atomic weight of sodium be=
22 x 28 + 23 x72
=2272/100
=22.72
Hence, 22.72 is the average atomic weight of sodium.
Learn more about isotopes here:
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The sum of the atomic masses of all the atoms in a compound is called the
A small windmill is to be built at a science competition. A large floor fan is used to power each windmill The task
is to lift a bucket filled with the most number of pennies possible from a height of one meter in one minute.
Which change in decision would most likely increase the weight that the windmill could lift?
A)
Make the fan blades smaller.
B)
Make the arms of the windmill longer,
C)
Make the arms of the windmill shorter
D)
Make the fan blades out of a lighter material.
Answer:
D
Explanation:
I'm doing USA test prep and I got it right
Answer:
Explanation:
It is D
Make the fan blades out of a lighter material.
I need help with chemistry question?
Answer:
2Al + 3Na2SO4 -----> Al2(SO4)3 + 6 Na
Explanation:
Product should be Al2(SO4)3
Because Al contains +3 charge
And SO4 contains -2 charge
To balance this postive and negative charge we multiple +3 with 2 and -2 with 3
Which elements are abundant in visible universe
Hydrogen is the most abundant element in the Universe; helium is second. However, after this, the rank of abundance does not continue to correspond to the atomic number; oxygen has abundance rank 3, but atomic number 8. All others are substantially less common.
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what happens when exhaled air passes through clear lime water?