Answer:
25 years.
Explanation:
From the question given above, the following data were obtained:
Original amount (N₀) = 10 g
Time (t) = 50 years
Amount remaining (N) = 2.5 g
Half-life (t½) =?
Next, we shall determine the number of half-lives that has elapse. This can be obtained as follow:
Original amount (N₀) = 10 g
Amount remaining (N) = 2.5 g
Number of half-lives (n) =?
N = 1/2ⁿ × N₀
2.5 = 1/2ⁿ × 10
Cross multiply
2.5 × 2ⁿ = 10
Divide both side by 2.5
2ⁿ = 10 / 2.5
2ⁿ = 4
Express 4 in index form with 2 as the base.
2ⁿ = 2²
n =2
Thus, 2 half-lives has elapsed.
Finally, we shall determine the half-life of the radioactive substance. This can be obtained as follow:
Time (t) = 50 years
Number of half-lives (n) = 2
Half-life (t½) =?
n = t / t½
2 = 50 / t½
Cross multiply
2 × t½ = 50
Divide both side by 2
t½ = 50 / 2
t½ = 25 years.
Thus, the half-life of the radioactive substance is 25 years.
The nucleus contains:
protons and electrons
protons and neutrons
electrons
protons, neutron, and electons
Explanation:
protons, neutrons and electrons
Answer:
An atom contains protons, neutrons and electrons BUT A NUCLEUS CONTAINS PROTONS AND NEUTRONS ONLY.
As a bond between a hydrogen atom and a
sulfur atom is formed, electrons are
A. shared to form an ionic bond
B. shared to form a covalent bond
C. transferred to form an ionic bond
D. transferred to form a covalent bond
it is b shared to form a covalent bond
Explanation:
A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.
What gas is used and what is released
a.carbon dioxide / oxygen
b.Oxygen/carbon dioxide
c.Carbon dioxide/helium
d.oxygen/calcium
Answer:
if i got it right i think it woud be a
2. Sate the method of collecting gases that are
ii). Lighter than ai
i). denser than air
Answer:
i) Upwards delivery
ii) Downwards delivery
Explanation:
The methods used in the collection of gases are quite different depending on the state of the gas. The solubility and density of gases are the factors that determine the method of collection to be used.
Upwards delivery is used to collect gases that are soluble in water and lighter compared to air. Examples of these kind of gases include; Cl2 and SO2
Downwards delivery is used to collect gases that are soluble in water and denser than air. An example of this kind of gas is ammonia gas, NH4.
Hydrochloric acid reacts with sodium hydroxide to form water and sodium chloride. Hydrochloric acid is an extremely acidic, clear, corrosive liquid. Sodium hydroxide is a very basic white solid.
What can be known about the reactants of this reaction?
They will be clear.
They will not have the properties of sodium hydroxide or hydrochloric acid.
They will be corrosive.
They will have the properties of sodium hydroxide or hydrochloric acid.
The answer is C.
You're welcome!
6. Certain materials can act as indicators because they change
a. Acidity
b. Color
c. Concentration
d. Taste
Answer:
B
Explanation:
Identify the three basic ingredients used in glass and give an example of each
Answer:
Sand (SiO2 silica) In its pure form it exists as a polymer, (SiO2)n.
Soda ash (sodium carbonate Na2CO3) ...
Limestone (calcium carbonate or CaCo3) or dolomite (MgCO3)
Explanation:
I am pretty sure you know what sand is, Soda ash is a fine white colored powder that is extracted from the ashes of plants growing in sodium rich soils. Limestone is is a common type of carbonate sedimentary rock.
What measurement describes the pressure of gas
Answer:
a manometer
Explanation:
A manometer can be used to measure the pressure of a gas. The (difference in) height between the liquid levels (h) is a measure of the pressure. Mercury is usually used because of its large density.
An alloy is an example of a
a.solid mixture but not a solution.
b.liquid solution.
c.solid solution.
d.gaseous solution.
determine the number of grams of carbon 3.14x 1023 atoms of carbon
6.26 g C
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableMolesAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
[Given] 3.14 × 10²³ atoms C
[Solve] grams C
Step 2: Identify Conversions
Avogadro's Number
[PT] Molar Mass of C - 12.01 g/mol
Step 3: Convert
[DA] Set up: [tex]\displaystyle 3.14 \cdot 10^{23} \ atoms \ C(\frac{1 \ mol \ C}{6.022 \cdot 10^{23} \ atoms \ C})(\frac{12.01 \ g \ C}{1 \ mol \ C})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 6.26227 \ g \ C[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
6.26227 g C ≈ 6.26 g C
All of the following are solutions except?
a.wine
b.fruitcake
c.a ruby
d.a brass penny
Answer:
fruit cake is the right ans
Answer:
Heyy mate
Explanation:
fruit cake is the correct answer
Hope it helps
Why do hurricanes occur near the equator and not further North? Why do they
become weaker as they hit the land?
Answer:
the occur near the equator bc its- bc its warm and they get weak bc it slows them down
Explanation:
Crystallisation description of method
Answer:
Crystallization is a method for transforming a solution into a solid, where a supersaturated solution nucleates the solute by a chemical equilibrium controlled process. Uniform particles with well-defined morphology are formed, and these readily re-dissolve
Explanation:
Answer:
Crystallization or crystallisation is the process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some of the ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.
4. "Metals are conductor of electricity"prove
Answer:
Hey mate.......
Explanation:
This is ur answer......
Metals are an excellent conductor of electricity and heat because the atoms in the metals form a matrix through which outer electrons can move freely. Instead of orbiting their respective atoms, they form a sea of electrons that surround the positive nuclei of the interacting metal ions.
Hope it helps!
mark me brainliest pls......
Follow me! :)
A double replacement reaction is a reaction in which one element replaces a similar element within a compound
True
False
Answer:
False
Explanation:
. What you’re describing is a displacement reaction.
Answer:
False, that is a single replacement reaction that you have described.
Explanation:
seven carbon chain with CH3 attached to second and third carbon
Answer:
2,3-dimethylheptane.
CH₃ - CH - CH-CH₂-CH₂-CH₂-CH₂
| |
CH₃ CH₃
Explanation:
Hello there!
In this case, according to the given instructions, it is possible to draw the organic chemical structure by connecting seven carbon atoms along the parent chain with two methyl substituents at the second and third carbon atoms; thus, the resulting structure is:
CH₃ - CH - CH-CH₂-CH₂-CH₂-CH₂
| |
CH₃ CH₃
Furthermore, the name would be 2,3-dimethylheptane according to the IUPAC rules for nomenclature.
Best regards!
7.5 g CaCl2.9H2O (1 mol / 273.1215 g) ( 1 mol CaCl2 / 1 mol CaCl2.9H2O ) ( 110.98 g / 1 mol ) =
I bet no one can solve this question......
Answer:
Equilibrium is shifted to left.
Increase in temperature favours the endothermic reaction. In the given reaction, the backward reaction is an endothermic reaction. So the backward reaction is favoured, so the equilibrium shifts towards left.
how many mole of diphosphorus pentoxide are represented by 2.63×10²⁶ molecules
Answer:
436.88 moles of P₄O₁₀
Explanation:
From the question given above, the following data were obtained:
Number of molecules of P₄O₁₀ = 2.63×10²⁶ molecules
Number of mole of P₄O₁₀ =?
From Avogadro's hypothesis,
6.02×10²³ molecules = 1 mole of P₄O₁₀
Therefore,
2.63×10²⁶ molecules = 2.63×10²⁶/6.02×10²³
2.63×10²⁶ molecules = 436.88 moles of P₄O₁₀
Thus, 436.88 moles of P₄O₁₀ are present in 2.63×10²⁶ molecules.
The adjacent sides are perpendicular.
The mass of a brick is 5 grams. If the brick is smashed into little pieces, the total mass of all the pieces will be
5 grams
o less than 5 grams
O more than 5 grams
What will the mass be if the brick was smashed
Answer:
I am not sure but i think it is 5 grams
Explanation:
because the total mass= 5g
so it is a physical change so no new substance is formed
so the total mass = total mass of all the broken pieces
Translation is the conversion of
1 .RNA to DNA.
2. DNA to RNA.
3. DNA to protein.
4. RNA to protein.
(WILL MARK BRAINLIEST)
Translation is the conversion of RNA to protein. The conversion of RNA to DNA is called reverse transcription.
What do you mean by Proteins?Proteins may be defined as natural-appearing, extremely complex substances that consist of amino acid residues joined by peptide bonds.
The process of translation occurs in the cytoplasm of the cells, while the process of transcription occurs in the nucleus itself.
The conversion of DNA to RNA is called transcription. While the proteins are never directly converted from DNA, it involves both processes of transcription followed by the translation.
Therefore, translation is the conversion of RNA to protein.
To learn more about Translation, refer to the link:
https://brainly.com/question/2449073
#SPJ2
write down the sp-notation for cl-37
What is the difference between an endothermic and an exothermic reaction?
ANSWER THE QUESTION FOR 67 POINTS!
Answer:
Endothermic Reaction:
These type of reactions are those reactions which absorb energy from the surroundings to form products. They also create a cooling effect in the surrounding as they absorb heat and thus the surrounding area gets cooled.
Exothermic Reaction:
These are reactions that release energy, mostly in the form of heat or light.
The products will release energy there can be a heating effect in the surroundings.
Water vapor also enters the atmosphere through —————(2 words), which takes place in many cells and produces water and carbon dioxide.
Answer:
It is photosynthesis and transpiration
hope it helps
GIVING 500 PTS Question 17 (1 point)
Chemical energy can be transformed into mechanical energy in a fan. However, what is the step that is missing from the diagram that shows how this transformation works?
Question 17 options:
magnetic energy
transformational energy
electrical energy
heat energy
Question 18 (1 point)
What is the difference between a generator and a motor?
Question 18 options:
A generator converts mechanical energy into electrical energy and a motor converts electrical energy into mechanical energy.
A generator converts electrical energy into mechanical energy and a motor converts mechanical energy into electrical energy.
A generator converts kinetic energy into mechanical energy and a motor converts mechanical energy into kinetic energy.
A generator converts potential energy into electrical energy and a motor converts electrical energy into potential energy.
Question 19 (1 point)
Which of these is an example of convection?
Question 19 options:
an egg boiling in water
an egg frying in a pan
an egg exposed to a flame
an egg warming under a light
Question 20 (1 point)
A rainstorm occurs on a hillside. Within hours, much of the water flows into a lake at the bottom of the hill. What will most likely happen to the rest of the water?
Question 20 options:
It will change into dew on plants along the hill.
It will become part of the groundwater flow.
It will form a cloud above the hill.
It will change from water into air.
Question 21 (1 point)
What is the Coriolis Effect?
Question 21 options:
the circulation route of trade winds moving from east to west
the way that tropical winds circulate to form hurricanes and large storms
the rapid movement of winds found in the upper atmosphere
he curved path of global winds due to the rotation of Earth
Question 22 (1 point)
Based on the weather map above, which statement is true based on the weather map?
Question 22 options:
A warm front is moving towards South Carolina bring rainy conditions.
A cold front just passed through South Carolina bringing cooler temperatures.
A warm front just passed through South Carolina bringing warmer temperatures.
A stationary front is moving towards South Carolina bringing long periods of rain.
Question 23 (1 point)
Which type of local wind is shown below and what causes this type of wind?
Question 23 options:
At night, cooler air over land replaces rising warmer air over water causing a land breeze.
At night cooler air over water replaces rising warmer air over land causing a land breeze.
During the day, cooler air over land forces warmer air over water to rise causing a sea breeze.
Question 24 (1 point)
An air mass, shown in the image below, that forms over parts of Mexico, Texas, and Arizona will be a _______.
Question 24 options:
continental polar air mass
continental tropical air mass
maritime polar air mass
maritime tropical air mass
Question 25 (1 point)
Which of these plants do not have special tissues to deliver food and water to its cells?
Question 25 options:
Maple
Dogwood
Tomato
Liverwort
Question 26 (1 point)
Where are the female reproductive organs of a flower found?
Question 26 options:
in the stamen
in the roots
in the pistil
in the petals
Question 27 (1 point)
What path do sperm cells take to get to egg cells during fertilization of a flowering plant?
Question 27 options:
Pollen lands on the stigma; pollen grain grows a tube down the style to an ovule; and fertilization occurs.
Pollen lands on an anther; grows a tube to the filament; and fertilization occurs.
Pollen lands on the stigma and fertilization of the stigma occurs.
Pollen lands on a newly formed seed and fertilization occurs.
Question 28 (1 point)
A green plant must be able to perform three different processes in order to survive. What are they?
Question 28 options:
respiration, perspiration, photosynthesis
transpiration, respiration, photosynthesis
chlorophyll, photosynthesis, perspiration
transcription, photosynthesis, chloroplast
Question 29 (1 point)
Which statement is a correct description of the processes of respiration and transpiration in a plant?
Question 29 options:
Transpiration is when the plant loses water through its leaves. Respiration is when the plant breaks down the sugar in its cells to release energy.
Transpiration is when the plant pulls water into its roots. Respiration is when the plant breathes.
Transpiration is when the plant grows over time. Respiration is when the plant breaks down the sugar in its roots.
Transpiration is when the plant produces buds. Respiration is when the plant dies.
Question 30 (1 point)
Which equation correctly describes photosynthesis?
Question 30 options:
water + sugar + oxygen → carbon dioxide + chlorophyll
sunlight + water + carbon dioxide → oxygen + sugar
sunlight + sugar → water + oxygen
carbon dioxide + oxygen → water + sugar + sunlight
Answer:
17. transformational energy
A gas is expanded from an initial volume of 1 L at 1 atm at 7 °C to a final volume of 5 L.
During the expansion the gas increases to 287 °C. What is the final pressure?
Answer:
0.40 atm
Explanation:
To answer this problem we can use the combined gas law:
T₂P₁V₁ = T₁P₂V₂In this case:
T₂ = 287 °C ⇒ 287 + 273.16 = 560.16 KP₁ = 1 atmV₁ = 1 LT₁ = 7 °C ⇒ 7 + 273.16 = 280.16 KP₂ = ?V₂ = 5 LWe input the data:
560.16 K * 1 atm * 1 L = 280.16 K * P₂ * 5 LAnd solve for P₂:
P₂ = 0.40 atmDuring the rock cycle, which of the following types of materials forms as a result of weathering and erosion of rock?
D » » DI
Which applies to fusion? Check all that apply.
involves the splitting of nuclei
takes place in the Sun
releaſes radiation as a waste product
occurs in nuclear power plants and is used to generate electricity
plays a role in the production of essentially all elements heavier than helium
releases large amounts of energy
I’m looking for fusion not fission
Answer:
The correct answer is -
takes place in the Sun
plays a role in the production of essentially all elements heavier than helium
releases large amounts of energy
Explanation:
Fusion reaction takes place when two or more small atomic nuclei come in close proximation for a longer time so the nuclear force pulling them together and form into heavier molecules than helium and releases a huge amount of energy by this process.
A great example of this fusion reaction is the sun where nuclear fusion takes place inside the core of the sun and result in a huge amount of release as it is an exothermic reaction.
Answer:
2, 5, 6Explanation
EDGE2021
A machine with three pulleys uses
force to do work than a machine with four pulleys.
more
less