Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.
Who made the first periodic table of the elements?
O A. Ernest Rutherford
O B. Dmitri Mendeleev
O C. Niels Bohr
O D. Henry Moseley
The periodic table was invented by Russian chemist Dmitri Mendeleev in 1869.
Answer:
B. Dmitri Mendeleev
Explanation:
Which kind of energy is stored in the chemical bonds of molecules found in
wood?
A. Mechanical energy
B. Potential energy
C. Gravitational energy
D. Kinetic energy
Answer:
B. Potential energy
Explanation:
It's not mechanical energy, because it is not doing work
It's not kinetic energy because it;s not moving
It's not gravitational energy because it is not above the ground
It is potential energy because it is stored energy
Explain how monumentum conservation is applied in ball games
Answer:
Hi , your answer is that At impact, the cue ball stops, but transfers all of its momentum and kinetic energy to the other ball, resulting in the hit ball rolling with the initial speed of the cue ball. In an inelastic collision, momentum is conserved, but the total kinetic energy of the system is not conserved
Explanation:
i really hope i helped , pleae give me brainliest , have a nice day and thank you in advance :) .
Which of the following statements regarding carbon is false? Group of answer choices Carbon has the capacity to form single and double bonds. Carbon has the ability to bond with up to six other atoms. Carbon has a tendency to form covalent bonds. Carbon has the ability to bond together to form extensive branched or unbranched "carbon skeletons."
Answer: The statement, carbon has the ability to bond with up to six other atoms is false.
Explanation:
Carbon is a group 14 element and it is a non-metal. The atomic number of carbon is 6 and its electronic distribution is 2, 4.
This means that there are 4 valence electrons present in it. Also, in order to attain stability a carbon atom forms only covalent bonds, that is, it shares its valence electrons with its own atoms or atoms of other elements.
Carbon has the capacity to form single and double bonds.
As valency of carbon is four so it can only combine to 4 other atoms vis single bond and it cannot bond with up to six other atoms.
Carbon shows the property of catenation, that is, it forms covalent bonds with its own atoms in a large number. So, carbon has the ability to bond together to form extensive branched or unbranched "carbon skeletons".
Thus, we can conclude that the statement, carbon has the ability to bond with up to six other atoms is false.
co2(g)+H20+148Kcal---->H2Co3 Endotérmica o exotérmica
endothermic
requires energy to occure
why do objects cool down
Answer:
wla dyan ang sagut ehh baka mali yan
How many centimeters are in 5 miles? Hint: 1 miles = 5280 feet
Considering the temperature vs. time graph below, how does the temperature at the beginning of a change of state
compare with the temperature at the end of the change?
Answer:
The temperature on the graph is higher at point 5 than at point 1. The correct answer is the last answer choice that you showed.
Explanation:
The temperature at point 1 is -10 degrees Celsius, while the temperature at point 5 is 120 degrees Celsius. This is a 1300% increase.
See the calculation here: https://www.calculatorsoup.com/calculators/algebra/percent-change-calculator.php?v_1=-10&v_2=120&action=solve
I hope this helps.
Question 14 of 30
Which of the following elements has 1 valence electron?
The Periodic Table
A. Sodium (Na)
B. Chlorine (CI)
C. Calcium (Ca)
D. Helium (He)
SUBMIT
Answer:
A. Sodium (Na)
Explanation:
The total number of electrons in the outermost principal energy level of an element is called the valence electrons of that element.
Na (11)---→1s2 2s2 2p6 3s1
There 1 electron in the outermost principal energy level of Sodium. So, the number of valence electron of Sodium is 11.
Answer:
Na
Explanation:
I was learning about it recently, that dude's right, it's Sodium
the rows from left to right in the periodic table is called what
Answer:
The periodic table has rows that go left to right and columns that go up and down, just like any other grid. The rows are referred to as PERIODS, while the columns are referred to as GROUPS.
Explanation:
Increasing the temperature of an endothermic reaction results in ____
· more reactants and products.
· no change in the quantities of reactants and products.
· more reactants and fewer products.
· fewer reactants and products.
· more products and fewer reactants.
Answer:
more reactents and products
PLEASE HELP : Arrange the following elements into a food chain: plants, snake, Sun, hawk, and mouse.
Answer:
Plants ➯ Mouse ➯ Snake ➯ Hawk ➯ Sun
Explanation:
In Order As A Food Chain
The elements are arranged into food chain like plants ⇒Mouse ⇒ Snake⇒ Hawk ⇒ Sun.
What is element?A substance that could not be further decomposed according to any chemical reaction is known as a chemical element.
What is food chain?
The flow of nutrients as well as energy through such an ecosystem is described by a food chain. Energy is first produced by plants at the most fundamental level, and then it is used by higher-level species like herbivores. Energy is then transmitted from one carnivore to the next when they eat the herbivores.
The elements are arranged into food chain like plants ⇒Mouse ⇒ Snake⇒ Hawk ⇒ Sun.
To know more about food chain and element
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Fill in the coefficients that will balance the following reaction:
Write the complete and net ionic equations for the following reactions. If only the reactants are given, predict the products and balance the equation first.
Explanation:
u can put them in order crossed are spectator ions. hope this helps:)
What are 3 things that
happen to your body when you start exercising
regularly?
Explanation:
Weight loss and weight maintenance.
Muscle gain.
Improved mood.
Improved heart health.
what are the characteristics or properties that you can use to classify elements
Answer:
The number of outermost energy level electrons ( valency electrons )
The atomic number
explain how ships made of steel float on water
Answer:
The air that is inside a ship is much less dense than water. That's what keeps it floating
How many moles of H2O
moles of H2O are needed to produce 55.7 moles of H2?
Answer: 55.7 moles of [tex]H_2O[/tex] are needed to produce the given amount of [tex]H_2[/tex]
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass.
The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given values:
Moles of [tex]H_2[/tex] = 55.7 moles
The chemical equation for the decomposition of water follows:
[tex]2H_2O\rightarrow 2H_2+O_2[/tex]
By the stoichiometry of the reaction:
If 2 moles of hydrogen gas is produced from 2 moles of water
So, 55.7 moles of hydrogen gas will be produced by = [tex]\frac{2}{2}\times 55.7=55.7mol[/tex] of water
Hence, 55.7 moles of [tex]H_2O[/tex] are needed to produce the given amount of [tex]H_2[/tex]
Taking into account the reaction stoichiometry,
Reaction stoichiometryIn first place, the balanced reaction is:
2 H₂O → 2 H₂ + O₂
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
H₂O: 2 molesH₂: 2 molesO₂: 1 moleMoles of H₂O requiredThe following rule of three can be applied: if by reaction stoichiometry 2 moles of H₂ are produced from 2 moles of H₂O, 55.7 moles of H₂ are produced from how many moles of H₂O?
[tex]moles of H_{2} O=\frac{55.7 moles of H_{2}x 2 moles of H_{2} O}{2 moles of H_{2}}[/tex]
moles of H₂O= 55.7 moles
Finally, 55.7 moles of H₂O is requiredto produce 55.7 moles of H₂.
Learn more about the reaction stoichiometry:
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Write the nuclear equation for the beta decay
of calcium-45.
Answer:
on https://www.ck12.org/book/peoples-physics-concepts/section/20.1/
Explanation:
it shows for calcium 45 and maybe a possible equation on 3/4th's scroll down?
Why don’t scientists use the Bohr model above to explain charge transfer?
Answer:
nsksbsjensnsjeiejensbsksks
calculate the oxidation numbers of the elements in this equation
2 Al2O3 → 4 Al + 3 O2
Explanation:
Answer
Open in answr app
The rule used here is that the algebraic sum of the oxidation numbers of all the atoms a molecule is zero.
Al2O32× ( oxidation number of Al)+3× ( Oxidation number of O ) = 0
2× ( Oxidation number of Al) +3(−2)=0
2× ( oxidation number of Al) +6
∴ Oxidation number of Al =+3
What happens to the freezing point of a solution when more solute is added?
How many liters of hydrogen (at 0.97atm and 24c) will produce 180 grams of water
I also need to know how to get the answer.
H₂ + ½O₂ → H₂O
2g → 18g
So, 18g water needs 2g H₂
So, 1g water needs 2/18g H₂
So, 180g water needs 2/18 x 180g H₂
→ 20 litres of H₂
Answer:
Explanation:
Molar mass of water, H2O = 2 + 16 = 18
So 180g of water contains 10M
H2 + O -> H2O
10M of Hydrogen is needed to produce 10M of water.
Molar volume at STP = 22.4L
So 10M of Hydrogen at STP = 224L
With Ideal Gas Law, P1V1/T1 = P2V2/T2
At STP, P1 = 1atm, T1=273K
At 0.97atm and 24c (273+24 = 297K), 10M of Hydrogen will take up:
1*224/273 = 0.97*V2/297
V2 = 224*297/273/0.97
= 251.23L
So the answer is 251.23L
What charge would Balloon #2 have? How did you determine this?
Answer:I belive it would be attracted seeing as how there are more magmatic charges on that side of no 2 and how there are more positive charges on the middle side of ballon no1.
Explanation:
1. How many molecules of S2 gas are in 756.2 L?
a. 2.032 x 1025 molecules S,
b. 3.022 x 1023 molecules S,
c. 4.302 x 10 molecules S
d. 8.203 x 10' molecules S2
Answer: There are [tex]2.032 \times 10^{25}[/tex] molecules [tex]S_{2}[/tex] gas are in 756.2 L.
Explanation:
It is known that 1 mole of any gas equals 22.4 L at STP. Hence, number of moles present in 756.2 L are calculated as follows.
[tex]Mole = \frac{Volume}{22.4 L}\\= \frac{756.2 L}{22.4 L}\\= 33.76 mol[/tex]
According to mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] molecules.
Therefore, molecules of S present in 33.76 moles are calculated as follows.
[tex]1 mol = 6.022 \times 10^{23}\\33.76 mol = 33.76 \times 6.022 \times 10^{23}\\= 2.032 \times 10^{25}[/tex]
Thus, we can conclude that there are [tex]2.032 \times 10^{25}[/tex] molecules [tex]S_{2}[/tex] gas are in 756.2 L.
Calculate the standard enthalpy change for the reaction 2A+B⇌2C+2D Use the following data: Substance ΔH∘f (kJ/mol) A -235 B -413 C 193 D -493
Answer:
ΔH = 283kJ/mol
Explanation:
Using Hess's law, the ΔH of a reaction is equal to the sum of ΔH° of products times its coefficient subtracting the sum of ΔH° of reactants times its coefficient. Replacing, for the reaction:
ΔH = 2ΔH°C + 2ΔH°D - (2ΔH°A+ΔH°B)
ΔH = 2*193kJ/mol + 2*-493kJ/mol - (2*-235kJ/mol+ (-413kJ/mol)
ΔH = 283kJ/molA doctor is testing a new medication and he doesn’t tell the people in the study about the possible side effects of the medicine. He is _____.
what is the molecular weight of a gas which diffuses 1/50 as fast as hydrogen
Which of the following pairs of elements is most likely to form an ionic compound?
• magnesium and sodium
• nitrogen and sulfur
• oxygen and chlorine
• magnesium and chlorine
• carbon and fluorine
Explanation:
magnesium and sodium because they are minerals and part of iron
Predict the product(s) of the following neutralization reaction. Type the balanced the equation.
HNO3 + Ba(OH)2
Answer:
The products from the neutralization reaction are barium nitrate and water.
The balanced chemical equation is
2 [tex]HNO_{3}[/tex] + 1 [tex]Ba(OH)_{2}[/tex] --> 1 [tex]Ba(NO_3)_{2}[/tex] + 2 [tex]H_{2}O[/tex].
