Answer:
41.25g
Explanation:
Given parameters:
Half-life of Technetium - 104 = 18minutes
Mass = 165g
Unknown:
Mass of sample remaining after 36minutes = ?
Solution:
The half-life of a radioactive element is the time taken for half of the element to decay;
Now;
Start First half life Second half-life
Time 0 18min 36min
Mass 165g 82.5g 41.25g
why we say the chemical property is a chemical change?
Answer:
In order to identify a chemical property,we look for a chemical change.Chemical changes involve chemical reactions and are often observed through a change in colour or odor
TIMED CHEMISTRY PLZ HELP How many selenium atoms are in the chemical formula for the compound formed when selenium is combined with lead(II)?
Answer: Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between the elements above
Explanation:
4. Imagine you have a radioactive sample containing both Virtualium and decayed atoms of Virtualium. After analysis, you find it contains 10 atoms of Virtualium and 40 decayed atoms. How old is your sample? (Hint: You must use the half-life of Virtualium determined earlier in the activity.)
Answer:
25
Explanation:
Sodium hydrogen carbonate and citric acid
Word equation
Answer:
the right answer is:
Explanation:
How to Balance: NaHCO3 + HC2H3O2 = NaC2H3O2 + CO2 + H2O|
Answer:
NaHCO3 +C6H8O7
Explanation:
these are the formulas of sodium hydrogen carbonate and citric acid
The element with 5 electrons in its 3d sublevel is...?
Answer:
manganese, Mn
Explanation:
From the question, we have;
The number of electrons in the 3d sub level = 5
The kind of element = d-block element
On the periodic table, the elements with electrons in the 3d-sublevel in increasing order are;
Sc, 3d¹ 4s²
Ti 3d² 4s²
V 3d³ 4s²
Cr 3d⁵ 4s¹
Mn 3d⁵ 4s²
Fe 3d⁶ 4s²
Co 3d⁷ 4s²
Ni 3d⁸ 4s²
Cu 3d¹⁰ 4s¹
Zn 3d¹⁰ 4s²
The elements with 5 electrons in their 3d-sublevel are chromium Cr and manganese, Mn however the electronic configuration of chromium is given as 3d⁵ 4s¹ rather than 3d⁴ 4s² due to the minor difference in the gap of energy between the 3d and the 4s orbital as such the element that has the main characteristic of 5 electrons in its 3d sub level is manganese, Mn.
(Please someone help me it’s urgent) I need to pass this
Here is the electron configuration for Arsenic. What does the superscript 3 in 4pº tell
us?
Ar: 152 252 2p 352 3p6 452 310 4p3
The superscript 3 in 4pº tell that there are 3 electrons in this orbital
Further explanationIn an atom there are levels of energy in the shell and sub shell
This energy level is expressed in the form of electron configurations.
There are 4 sub-shells in the shell of an atom, namely s, p, d, and f. The maximum number of electrons for each sub-shell is
• s: 2 electrons
• p: 6 electrons
• d: 10 electrons and
• f: 14 electrons
Charging electrons in the sub-shell uses the following sequence:
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.
Arsenic is an element with the symbol As, which has an atomic number of 33 and a mass number of 75
Electron configuration of As : [Ar] 3d¹⁰4s²4p³
Each superscript shows the number of electrons that occupy each orbital
For the p orbital there are a maximum of 6 electrons, while the 4p³ orbital shows that there are 3 electrons in this orbital
10 g of copper is heated and the mass increases to 12.5 g. What is the mass of the copper in the new substances?
Answer:
10g
Explanation:
The amount of copper in the heated mass of the new substance produced is still 10g because in any chemical action, mass is always conserved.
According to the law of conservation of matter "matter is neither created nor destroyed in a chemical reaction". The change in mass is only due to oxygen gas that combines with the new copper formed or other substances that joined the mass. The substance will still have the same amount of copper as the original one. Since we started with 10g of copper, we end with 10g of copper.For her science project, Paula wants to determine if the growth of bacteria in standing rainwater changes over time. She collects rainwater and distributes it evenly in 6 jars and places them all indoors in a spot that does not receive a lot of sunlight to limit evaporation. Using a bacteria testing kit, she measures the bacteria in the water in the first jar on the 5th day, second jar on the 7th day, third jar on the 9th day, fourth jar on the 14th day, fifth jar on the 20th day, and sixth jar on the 24th day. What is the independent or manipulated variable in Paula's experiment?
Answer:
The correct answer is - the number of days the rainwater stands in the jars.
Explanation:
The independent variable or the manipulating variable is a variable in a research or study is the variable which affects the dependent variable or the variable that is going to measure in the study.
In the study, variables that recieves the treatment and changed in every subject are independent variables and in this study number of days the rainwater standing in various jars that might affect the growth of the bacteria in rainwater.
If, in the reaction below, 49 grams of Fe3O4 produces a 78.25% yield of Fe. How many grams are produced?
Really need help on this please, I’ll give brainliest!!
Where in your cells does cellular respiration occur?
Mitochondria
cytoplasm
nucleus
golgi bodies
Answer:
Mitochondria
Explanation:
The enzymatic reactions of the cellular respiration begin in the cytoplasm, but most of the reactions occur in the mitochondria.
Answer:
Cellular respiration is the multi-step process that creates energy from nutrients and food molecules. It begins in the cytoplasm of the cell, with the mitochondria functioning as the main organelle where the rest of the process continues and finishes. During respiration, glycolysis occurs in the cytoplasm of the cell.
Explanation:
What is the total number of electrons in mg
Answer:
12 electrons
Explanation:
For the element magnesium, there are 12 electrons. It means that there are 12 electrons in a magnesium atom.
Hope this helped!
PLEASE HELP ME!!! DUE TODAY
k=4 c=2 o=3
I think that is right if it is not this is what I would do go on google and look it up yes it takes a while to get what you want but you are sure it is right I am sorry that I can not do more for you and if this is wrong i am sorry for that too.
Answer:
19. K=8 c=4 o= 12
20. k=2 c=1 o=3
21. n=12 o=30
22. Cl=16 o=8
23. ca=1 c=4 h=6 o=4
24. Na=12 Br=12
25. Na=3 H=3 c=3 o=9
26. Ga=10 Cr=30 o=105
27. fe=8 o=12
28. ba=6 Mn=12 o=48
I WILL GIVE BRANLIEST What factor is a river in an ecosystem? Abiotic or Biotic?
Answer:
River ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts.
Explanation: it should be both
Answer:
Ecosystems mostly consist of both - abiotic and biotic factors. For that reason the answer which would properly address your question would be A - biotic and abiotic factors. Biotic factors are considered to represent the part of nature that are living and affect other organisms while abiotic factors are things which do not affect other living compounds.
at least three everyday things that exist or occur because of science.
Answer:
1.A POWER DRILL COULD SET YOUR HOUSE ON FIRE, IN THEORY.
2.STICKY NOTES COME OFF EASILY BECAUSE THEIR ADHESIVE IS UNEVEN. ...
3.GUM IS CHEWY BECAUSE IT'S MADE OF RUBBER. ...
4.OFFICE BUILDINGS ARE EVER-SO-SLIGHTLY TALLER AT NIGHT. ...
5.A LEGO BRICK CAN SUPPORT 770 POUNDS OF FORCE. ...
6.POLISHING SHOES IS LIKE FILLING IN A ROAD'S POTHOLES.
Explanation:
what does primary succession end with
I need help pretty bad can you answer all these questions
abiotic are non living things and biotic are living beings
Eukaryotic:these are developedand complete cells with well developed nucleus
PROKARYOTIC:these are primitive and incomplete cells without well developed nucleus difference between autotrophs and heterotrophs AUTOTROPHS :these are the organism which make their own food by photosynthesis
Heterotophs :these are the organism which depend on other organism for food
KINGDOMS:Monera
Protista
fungi
plantae
animalia
TAXONOMY IS the branch of biology that deals with the identification,nomenclature and classification of organism
2. What properties do all acids have?
3. Why should you never use taste as a method for testing an unknown substance?
4. What is used to detect the presence of acids?
10. What can you use to detect the presence of a base?
11. What are some common bases that we use every day?
12. How does an antacid help reduce heartburn?
13. What happens when acid and base are mixed
14. What is used to determine the pH of a substance?
15. Describe how the pH scale works. In other words, what is it actually measuring?
17. Why is pH important to our environment?
18. Describe how salt is formed.
Pls help!!!!!
Cream from milk can be separated by
process ......................................
Answer:
centrifugation
Explanation:
When the following equation is balanced, what is the coefficiant for Br?
___I2 +___NaBr rightwards arrow___NaI +_?_Br2
A.
6
B.
3
C.
1
D.
2
1 points
QUESTION 10
The previous question is an example of what type of chemical reaction?
A.
Synthesis
B.
Decomposition
C.
Single Re-Placement
D.
Double Re-Placement
Answer:
1. A 2. C
Explanation:
because it just is
HELP ASAP ILL GIVE YOU 40 POINTS IF YOUR CORRECT!
A teacher wrote the following part of a balanced chemical equation:Cu + 2AgNO3 →To show the conservation of matter in the chemical reaction, how many silver (Ag) atoms will be needed on the right-hand side of the balanced equation?
Answer:
Figure 7.4.1 : Balancing Equations. You cannot change subscripts in a chemical formula to balance a chemical equation; you can change only the coefficients. Changing subscripts changes the ratios of atoms in the molecule and the resulting chemical properties. For example, water (H2O) and hydrogen peroxide (H2O2) are chemically distinct substances. H2O2 decomposes to H2O and O2 gas when it comes in contact with the metal platinum, whereas no such reaction occurs between water and platinum. The subscripts are part of the formulas and once the formulas for the reactants and products are determined, the subscripts may not be changed. The coefficients indicate the number of each substance involved in the reaction and may be changed in order to balance the equation. The equation above indicates that one mole of solid copper is reacting with two moles of aqueous silver nitrate to produce one mole of aqueous copper (II) nitrate and two atoms of solid silver.
Explanation:
Answer: 6
Explanation:
Element Quantity
Copper 1
Silver 2
Nitrogen 1
Oxygen 6
Can someone help? Ill give brainliest!
Directions: count each side of the reaction. Circle yes or no if it follows the law of conservation of mass
Answer:
Yes, it becomes 2 of H20 which is water
2 of 4
+ Automatic Zoom
10. The molar mass of CS2 is 76.14 g/mol. How many grams of CS2 are present in 10.00 mol?
Answer: C
Explanation:
There are 761.4 grams of CS2 in 10.00 mol.
To calculate the amount of grams present in a given amount of moles, the molar mass of the substance must be used, as follows:
[tex]m = MM \times mol[/tex]
In this way, just perform the following operation:
[tex]m = 76.14 \times 10[/tex]
[tex]m = 761.4 grams[/tex]
Thus, there are 761.4 grams of CS2 in 10 mol of the substance.
Learn more about mole calculation in: brainly.com/question/15693285
A student made 50g of sodium acetate , 20g of water and 15g of carbon dioxide by reacting baking soda with vinegar. How many total grams of baking soda and vinegar did the student react?
Answer:
Reacting of 5 cm3 of baking soda with 100 cm3 of vinegar should produce 0.083 moles of CO2 gas, 0.083 moles of sodium acetate, and leave 0.01 moles of sodium bicarbonate unreacted.
Explanation:
Someone tell me if I did the equation correctly or not.
Reaction between aqueous Washing soda and lemon juice=
3Na2Co3 + 2C6H8O7 = 2Na3(C6H3O7)+3CO2 (g) + 3H2O(l)
Sodium Carbonate commonly known as Sodium Carbonate is a inorganic compound which used in detergents and to soften the water. Its chemical formula is [tex]Na_{2}CO_{3_[/tex]. It is carbonate base
Lemon Juice:Lemon juice contain citric acid whose chemical formula is [tex]C_{6} H_{8} O_{7}[/tex]. Citric acid is a weak organic acid thus It is used for disinfectants and cleaning as well.
_____________________________________Reaction b/w Washing Soda and Citric AcidWhen Lemon Juice and Washing Soda react, the reaction is just an acid-base reaction and forms trisodium citrate and carbonic acid. The latter is then dissociated into Carbon Dioxide and Water. Carbon Dioxide escapes in the form of bubbles and Sodium Citrate(salt) and Water behind.
(citric acid)+ (sodium carbonate)= (trisodium citrate)+(water)+(carbon dioxide)
OR[tex]2C_{6}H_{8}O_{7} + 3Na_{2}CO_{3} ---> 2Na_{3}(C_{6} H_{3} O_{7})_{2} + 3H_{2}O + 3 CO_{2}[/tex]
_____________________________________Best Regards,'Borz'secondary alcohol (X) reacts with PCL5 to give alkyl halide (Y) which on dehydrohalogenation yield an alkene(Z).The alkene upon ozonolysis gives the mixture of ethanal and methanal.Identify X ,Y ,Z
Answer:
X = 2-propanol
Y = 2-chloropropane
Z = propene
Explanation:
Secondary alcohol is an alcohol in which the carbon that the functional group (OH group) is attached to is also attached to two alkyl group. Examples are 2-propanol and 2-butanol.
The secondary alcohol referred to in the question here is 2-propanol and it reacts with PCl₅ as seen below
H₃C-CH-CH₃ + PCl₅ ⇒ H₃C-CH-CH₃ + HCl + POCl₃
| |
OH Cl
The alkylhalide produced there is 2-chloropropane. Thus, we can see that X is 2-propanol and Y is 2-chloropropane.
When this 2-chloropropane undergoes dehydrohalogenation (removal of hydrogen and halogen) an alkene is formed. The reaction is seen below
H₃C-CH-CH₃ (-HCl) ⇒ H₃C-CH=CH₂
|
Cl
The alkene produced (as seen above) is propene.
Confirmation: When propene undergoes ozonolysis, the compounds produced are ethanal and methanal as seen in the equation below
O
/ \
H₃C-CH=CH₂ + O₃ ⇒ H₃C - CH CH₂ [-O] ⇒ CH + CH₂
|| || || ||
O O O O
The final products as seen above are methanal and ethanal
anyone help me with these
CORRECT ANSWERS
3. Does the siren of a moving police car seem to change pitch to the
police officers inside the car? Why or why not?
Answer:
As the police car moves towards them, the pitch of the police car's siren goes up because the sound waves get closer together in front of the police car. When the police car moves away from the person, the pitch goes down because the waves spread out behind the police and that makes the frequency go down.
Explanation:
Substance A dissociates 100% in water to produce H3O+ ions while substance B dissociates 25% in water to produce OH- ions. What can be determined from this information?
A:Substance A is a strong acid and substance B is a weak base
B:Substance A is a weak acid and substance B is a strong base
C:Substance A is a strong base and substance B is a weak acid
D:Substance A is a weak base and substance B is a strong acid
Answer:
A:Substance A is a strong acid and substance B is a weak base
Explanation:
From this information, we can conclude that substance A is a strong acid and substance B is a weak base.
A strong acid is one that ionizes completely in solution. Most strong acids are usually concentrated. 100% dissociation is a complete ionization.
A weak base ionizes slightly in an aqueous solution. 25% dissociation is weak ionization.
Answer:
a
Explanation:
2. A car travels at 65 miles/hr for 4.5 hours from Houston to Dallas. What is the
distance from Houston to Dallas?
What historical data from Tokyo could have helped in the development of tokyo's new flood protection system?
Answer: This historical data could have helped with the development of Tokyo’s new flood protection system:
historical frequency of flooding
amount of flooding during each storm
computer models forecasting the worst possible flooding
Explanation:
The frequency of flooding can help Tokyo measure when the next flood will be.
The amount of flooding can help Tokyo determine how much water will come during the flood.
And computer models forecasting the worst possible flood can help reach out to people and tell whether they need to evacuate or what they should plan for.