Answer: B. Magnesium, strontium, radium, barium
Explanation:
Elements are distributed in groups and periods in a periodic table.
Elements that belong to same groups will show similar chemical properties because they have same number of valence electrons.
Magnesium (Mg) , Strontium (Sr) , Radium (Ra) and Barium (Ba) are elements which belong to Group 2. They have 12, 38, 88 and 56 electrons respectively and contain 2 valence electrons each and need one electron to complete their octet.
The chemical reactivity of elements is governed by the valence electrons present in the element and thus they are alike in physical and chemical properties.
What would be the oxidation number of the atoms in these compounds?
Answer:
Oxidation state] is defined as the charge an atom might be imagined to have when electrons are counted according to an agreed-upon set of rules:
The oxidation state of a free element (uncombined element) is zero for a simple (monoatomic) ion, the oxidation state is equal to the net charge on the ion.
Hydrogen has an oxidation state of 1 and oxygen has an oxidation state of −2 when they are present in most compounds. (Exceptions to this are that hydrogen has an oxidation state of −1 in hydrides of active metals, e.g. LiH, and oxygen has an oxidation state of −1 in peroxides, e.g. H2O2 the algebraic sum of oxidation states of all atoms in a neutral molecule must be zero, while in ions the algebraic sum of the oxidation states of the constituent atoms must be equal to the charge on the ion.
The same is written in my textbook. But how am I supposed to find the ox. number of an atom, which is in compound like K2UO4?
How many atoms are contained in 12.8 g of Beryllium?
A9.0 atoms
B9.0 x 10 23 atoms
C8.55 atoms
D8.55 x 1023 atoms
Answer:
a atoms
Explanation:
Answer:
C. 8.55 atoms
Explanation:
Which of the following metals would be the best to choose for making jewellery? Aluminium, iron, copper or gold?
Answer:
Of course the answer is gold
Explanation:
Gold is used for making jewellery and not aluminium,iron or copper
Answer:
copper or gold.
Explanation:
Copper is also a good material for accessories. Even in the ancient times, those who can’t afford gold jewelry wear copper jewelry instead. It offers design flexibility too due to its high ductility.
determining the molecular formula of a hydrocarbon with a relative molecular mass of 54
Answer:
C₄H₆
Explanation:
A hydrocarbon is a molecule that only contains atoms of Carbon and Hydrogen. As you remember, the molar mass of Carbon is 12g/mol and the molar mass of Hydrogen is 1g/mol.
To solve this question we can find the amount of Carbons necessary that doesn't exceed the 54g/mol. That is:
54g/mol / 12g/mol = 4.5
As the molecular formula must be given in whole numbers, the amount of Carbons is 4. This 4 carbons have a mass of:
12g/mol*4 = 48g/mol
And the hydrogens necessaries to suply the molecular mass are:
54 - 48 = 6 hydrogens
That means molecular formula is:
C₄H₆*Riddle!* *Riddle!!* *Riddle!!!*
Answer these *science riddles*
1. What kind of chemical element hates to be a follower?
2. I come as a gas and I get in line with neon. I am also known as the home of a very super person. What am I?
3. What two periodic elements, when combined, heal?
4. What is black when you buy it, red when you use it, and gray when you throw it away?
5. I'm a god and also a planet and the same time I am a measure of heat. Who am I?
6. What goes up and down stairs without moving?
7. Give it food and it will live; give it water and it will die.
8. What can you catch but not throw?
9. I run, yet I have no legs. What am I?
10. Take one out and scratch my head, I am now black but once was red.
11. Remove the outside, cook the inside, eat the outside, throw away the inside.
12. What goes around the world and stays in a corner?
13. What gets wetter the more it dries?
14. The more there is, the less you see.
15. They come at night without being called and are lost in the day without being stolen.
Answer:
https://www.getriddles.com/science-riddles/
Explanation:
go to this link, you will find some answers
hope it helps!
How do I balance
H2O ⇾ H2 + O2
Chromatogram results are considered to have better resolution if the RF values of the components being separated or further apart rather than closer together
Answer:
False
Explanation:
False : It is better they are closer together
The RF ( retention factor ) is calculated with this formula
= distance travelled / distance travelled by solvent
And the larger the RF factor of a compound the less polar the compound ( i.e. it will not stick to the stationary phase ) hence it is better the RF values of the components to be closer
Answer:
True
Explanation:
The resulting Rf factor, which has no units, is dependent upon the specific stationary and mobile phase used. Chromatogram results are considered to have better resolution if the Rf values of the components being separated are farther apart (e.g. 0.3 and 0.7) rather than closer together (e.g. 0.4 and 0.5). The distance the compound moves relative to the distance the solvent (or mobile phase or eluent) moves is a characteristic of that compound. (where Rf is equal to distance compound moved divided by solvent front distance)
Only awnser #5#6#7#8 please 20 points! And i will mark brainliest.
Answer:
5. radiative zone 6. 27 million degrees Farenheit 7. photosphere 8. approximately 25 million degrees Farenheit if using the calculation for the core temperature of the sun at 27 million degrees as the corona is 2 million degrees
Explanation:
The process by which sand is formed from rocks are...
Question 1 options:
melting and cooling
compaction and cementation
heat and pressure
weathering and erosion
Answer:
weathering and erosion
Explanation:
Sand forms when rocks break down from weathering and eroding over thousands and even millions of years. Rocks take time to decompose, especially quartz (silica) and feldspar. Often starting thousands of miles from the ocean, rocks slowly travel down rivers and streams, constantly breaking down along the way.
Answer:
weathering and erosion
Someone help please?- Ill give brainilist.
Answers:
1. Carbon is to organic as silicon is to inorganic
2. Sugar is to carbohydrate as oil is to lipid
Pls answer asap! NO ATTACHMENTS!!!
Select the correct answer.
What does an atom gain or lose in an oxidation-reduction reaction?
A.
protons
B.
oxygen
C.
neutrons
D.
electrons
Answer:
D The atom gains an electron in an oxidation-reduction reaction.
1. What is the molar mass of sodium?
11
O
45.90
23
О
16
Answer:
11
Explanation:
Sodium is a chemical element with the symbol Na and atomic number 11.
Answer:
22.99g/mol (in this case 23g/mol)
Provide a set of step by step instructions to make 750 mL of 1.5 M calcium chloride solution.
Answer: PLease see answer in explanation column
Explanation:
FIRST STEP
We find the grams ( mass ) of solute required to prepare the solution by using the formula
grams ( mass ) of solute, g(CaCl2)= Molar mass x Molarity of the solution x Volume of the solution
Therefore Preparing 750 mL of 1.5 M calcium chloride solution, we have that Molar mass of Calcium chloride =110.98 g/mol
g(CaCl2) =110.98 g/mol X 1.5mol/L X 0.75L
g(CaCl2) =124.8525g CaCl2
SECOND STEP
Now Dissolve 124.8525g CaCl2 in about 350ml of distilled water then add more water until the final volume be comes 750ml
Most of the matter making up the earth is composed of
A. gases
B. compounds
C. mixtures
Most of the matter making up earth is composed of compounds. I think
How many grams is 2.40 x 1023 molecules of N,O,? (5 pts)
PLS HELP ASAP
Answer:
30.26 grams of N₂O₃
Explanation:
Divide by Avogadro's number. This leaves you with the number of moles. Then, multiply by the molar mass of N₂O₃
What is the percent by mass concentration of 1000 ml of a solution (d=1.5 g/ml) that contains 50 g of solute in it?
Answer: The percent by mass concentration is 33.3 %
Explanation:
Mass percent is the ratio of mass of solute to the mass of solution in terms of percentage.
mass of solute = 50 g
mass of solution = [tex]{\text {density of solution}}\times {\text {volume of solution}}=1.5g/ml\times 1000ml=1500g[/tex]
Mass percentage = [tex]\frac{50g}{1500g}\times 100\%=33.3\%[/tex]
Thus percent by mass concentration of 1000 ml of a solution (d=1.5 g/ml) that contains 50 g of solute in it is 33.3 %
why is the absolute dating of rocks important?
Answer:
The dating of rocks is important because:
Explanation:
its important to know how the rocks have changed.
A 5.0-g sample of Substance X increases in temperature from 20.0°C to 22.0°C when it absorbs 9.6J of heat. What is the specific heat of
Substance X in J/g °C)?
Answer:
0.96 J/g °C
General Formulas and Concepts:
Thermochemistry
Specific Heat Formula: q = mcΔT
m is mass (in grams)c is specific heat (in J/g °C)ΔT is change in temperature, final - initial (in °C)Explanation:
Step 1: Define
[Given] m = 5.0 g
[Given] ΔT = 22.0 °C - 20.0 °C = 2.0 °C
[Given] q = 9.6 J
[Solve] c
Step 2: Solve for c
Substitute in variables [Specific Heat Formula]: 9.6 J = (5.0 g)c(2.0 °C)[Specific Heat] Multiply: 9.6 J = (10. g °C)c[Specific Heat] Isolate c: 0.96 J/g °C = c[Specific Heat] Rewrite: c = 0.96 J/g °CExplain how subscripts are used when counting atoms in a compound
Answer:
The number of atoms of each kind is indicated by a subscript following the atom. If there is only one atom, no number is written. If there is more than one atom of a specific kind, the number is written as a subscript following the atom.
10. What is the Kinetic Energy of a 100 kg object that is moving with a speed of 13.5 m/s?
Answer:
[tex]100 \times 13.5 = ikw n bahaa[/tex]
IKAW na mag tayms
explain how of hope's apparatus can be used to demonstrate anomalous behaviour and water class 10
Answer:
The anomalous expansion of water refers to the fact that water, unlike most substances, expands when it freezes. The density of water increases as temperature decreases, but reaches a maximum at 4 degrees C then begins to expand. The significance of this is that ice is less dense than water so it floats in water.
This is of major biological importance. Lakes, ponds and streams freeze from the top down instead of from the bottom.
answer truthfully:))
Answer:
b) velocity.
c) velocity, m/s²
d)change in velocity, change in direction, change in both velocity and direction.
e) increasing or decreasing
Help please!!! I'll name you brainliest!!
Answer: pls mark brainliest
Explanation: i think so its D
In a redox reaction,
the oxidizing agent undergoes oxidation
the reducing agent undergoes reduction
the oxidizing agents undergoes reduction
O the oxidizing agent loses electrons
Answer:
the oxidizing agent undergoes oxidation and
the reducing agent undergoes reduction simultaneously
What causes polar bonds
Answer:
Bonds are polar when one element in a compound is more electronegative than the other. This creates a dipole in the molecule where one end of the molecule is partially positive and one end is partially negative
Explanation:
b) How many moles of Na2O can be produced from 13.5 moles Na?
Answer: 6.75 moles of [tex]Na_2O[/tex] can be produced from 13.5 moles Na
Explanation:
The balanced chemical equation for formation of [tex]Na_2O[/tex] from Na is:
[tex]4Na+O_2\rightarrow 2Na_2O[/tex]
According to stoichiometry :
4 moles of Na give = 2 moles of [tex]Na_2O[/tex]
Thus 13.5 moles of [tex]Na[/tex] give =[tex]\frac{2}{4}\times 13.5=6.75moles[/tex] of [tex]Na_2O[/tex]
Thus 6.75 moles of [tex]Na_2O[/tex] can be produced from 13.5 moles Na
In H20 does the 2 apply to
Hydrogen, Oxygen, or Both?
Answer:
The difference is due to the fact that one water molecule has two hydrogen atoms to one oxygen atom, as explained above. This means it takes two water molecules (2 H2O) to make one oxygen molecule (O2)
Explanation:
Answer:
In H20 does the 2 apply to Hydrogen
Explanation:
In H₂O there is two atoms of hydrogen and 1 atom of Oxygen
Hence, In H20 does the 2 apply to Hydrogen
-TheUnknownScientist
what is a pure substance?
Answer:
A pure substance is a substance or an element whose impurities are extracted by concentration by chemical means.
e.g Aluminium is made pure by concentration of it's ore, bauxite by treatment with excess Sodium Hydroxide solution.
B.Use the words inside the box to complete the chart below
Answer:
Answered below
Explanation:
>> ice is solid
>> water is liquid
>> Steam is gas
>> Ice → water = melting
>> water → steam = evaporation
>> steam → water = condensation
>> water → ice = freezing