Answer:
42 days
Explanation:
Half life = 8.4 days
Starting mass = 40.0 g
Time = ?
Final Mass = 1/16 * 40 = 2.5 g
First Half life;
Remaining mass = 40 / 2 = 20g
Second Half life;
Remaining mass = 20 / 2 = 10g
Third Half life;
Remaining mass = 10 / 2 = 5g
Fourth Half life;
Remaining mass = 5 / 2 = 2.5g
Time = Number of half lives * Duration of half life = 5 * 8.4 = 42 days
A hydrochloric acid solution contains 36 percent HCl by mass. Calculate its
molality
PLEASE HELP ME, EMERGENCY SITUATION (50 points)
207.86 grams of uranium (V) hydroxide reacts with 155.78 grams of thorium disulfate, which is the limiting reactant? You must prove your answer by showing the necessary work and explaining your answer choice.
Answer:
Thorium disulfate
Explanation:
Thorium also forms insoluble compounds with fluoride, sulfate, ... hydroxide from solutions of pH 3.6 or above. ... rate should be about 2.5 g/min, and the reaction tube temperature ... thenoyl group decreases the solubility of the reagent in the aqueous
How many valence electrons are there in Se atom?
Answer:
4 valence electrons
Despite the fact that the word silicon has a ubiquitous affiliation with all things electronic, Si itself is not a good electrical conductor. It has 4 valence electrons, meaning that filling its outer shell it can form a very strong lattice with 4 neighboring Si atoms-with no un-bonded electrons remaining
Answer:
The numer of valence electrons is defined as the number of electrons present in the outer most shell of the atom.So, in the case if selenium, there are 6.
what's a vacuum exactly
Answer:
Vacuum: space in which there is no matter or in which the pressure is so low that any particles in the space do not affect any processes being carried on there It is a condition well below normal atmospheric pressure and is measured in units of pressure (the pascal).-the internet gave me this answer so..
Explanation:
hope this helps :)
Determine the moles of chlorine needed to react with 38.9 of iron (III) chloride.
2 Fe+3 CI, - 2 Feci
Answer: 0.360 moles
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} FeCl_3=\frac{38.9g}{162.2g/mol}=0.240moles[/tex]
The balanced chemical reaction is:
[tex]2Fe+3Cl_2\rightarrow 2FeCl_3[/tex]
According to stoichiometry :
2 moles of require = 3 moles of
Thus 0.240 moles of [tex]FeCl_3[/tex] will require=[tex]\frac{3}{2}\times 0.240=0.360moles[/tex] of [tex]Cl_2[/tex]
Thus 0.360 moles of chlorine needed to react to produce 38.9 of iron (III) chloride.
Consider the equation for the formation of a kidney stone.
2Na3 PO4 (aq) + 3CaCl2 (aq) =
Ca3(PO4)2 (s) + 6NaCl (aq)
Is each reactant bonded ionically or covalently?
How do you know?
Answer:
Ionically, because they are ionic compounds
How much force is required to accelerate a 22 kg mass at 6 m/s2?s
Answer:
F=132k.gm/s^2Explanation:
F=m×af=22k.g×6m/s^2f=132k.gm/s^2What is the main difference between weathering and erosion?
Answer:
Erosion occurs when smaller rock fragments (now pebbles, sand, or soil) are displaced by natural forces. Weathering occurs as a rock is altered or destroyed but remains in place. The displacement of weathered rock fragments is referred to as erosion.
Explanation
In which ways are evaporation and condensation similar?
Both cause decrease in air temperature
Both cause increase in air temperature
Both are caused by the warming of the atmosphere
Both are caused by changes in heat energy
Answer:
Both are caused by changes in heat energy
Explanation:
When air gets hotter water will evaporate, when air gets cooler water will condensate.
Type of introduction
Answer:
Five Types of Introductions.
“Inquisitive” Explain why your subject is important, curious, or interesting.
“Paradoxical” Explain what aspects of your subject seem improbable. ...
“Corrective” Explain how your subject has been misunderstood or misrepresented by others. ...
7. A bicycle rider is traveling up a hill. When the rider reaches the top of the hill, she
stops to rest. Then she travels down the hill. The diagram shows the rider in the
three different positions,
Which of these correctly describes the potential energy and kinetic energy of the bicycle rider ? I NEED HELP FAST !!
A bee buzzes inside a flower to drink some nectar. While there it touches the stamen. Later the bee goes to another flower and comes into contact with the flower's pistil. Which process of reproduction is this helping with?
QUESTION
A bee buzzes inside a flower to drink some nectar. While there it touches the stamen. Later the bee goes to another flower and comes into contact with the flower's pistil. Which process of reproduction is this helping with?
ANSWER
The bee is helping in pollination which is an important event in case of sexual reproduction in flowering plants.
Pollination is a part of pre-fertilisation ( gamete transfer ).
Pollination by insects ( most commonly bees ) is known as Entamophily
If you can solve both
Will mark brainly
ASAP
Answer:
The main function sis the 2nd one and the substance provides the first 1.
Explanation:
Hope you finish the rest on your own, have fun!
A tank containing 5.00 L of nitrogen at 75.0 atm pressure and 28.0 C is left standing in sunlight. Its temperature rises to 50.0C. What is the pressure at this higher temperature?
Answer:
80.5 atm
Explanation:
First of all, we convert 28.0 °C and 50.0 °C into K:
28.0 + 273.16 = 301.16 K50.0 + 273.16 = 323.16 KTo answer this problem we'll use Gay-Lussac's Law, which states that:
T₁*P₂=T₂*P₁In this case:
T₁ = 301.16 KP₂ = ?T₂ = 323.16 KP₁ = 75.0 atmWe put the data:
301.16 K * P₂ = 323.16 K * 75.0 atmAnd solve for P₂:
P₂ = 80.5 atmThus, the correct answer is 80.5 atm.
- What is the percent yield if your actual yield is 39.78g and your theoretical
yield was 47.84 g?
Which of the following is NOT an example of a chemical reaction?
A. a candle burning forming carbon dioxide
B. sodium and chlorine forming salt
C. a marshmallow releasing carbon when burned
D. ice turning into water
Between what time interval was the object moving the slowest?
Between what time interval was the object moving the fastest
Answer:
from 1 to 2 hour the object was moving the slowestfrom 4 to 5 hours the object was moving the fastestwhy do atoms become anions and cations
Answer:
Cations (positively-charged ions) and anions (negatively-charged ions) are formed when a metal loses electrons, and a nonmetal gains those electrons. ... And all of them form an anion with a single negative charge. The VIA elements gain two electrons to form anions with a 2- charge.
Explanation: OR
Metallic atoms hold some of their electrons relatively loosely. Consequently, they tend to lose electrons and form cations. Conversely, most nonmetallic atoms attract electrons more strongly than metallic atoms, and so gain electrons to form anions.
Metallic atoms hold some of their electrons relatively loosely. Consequently, they tend to lose electrons and form cations. Conversely, most nonmetallic atoms attract electrons more strongly than metallic atoms, and so gain › cat...
_
Answer:
It gains one or more electrons from another atom to become negatively charged.
Explanation:
An atom becomes charged by either gaining or losing electrons, and is called an ion. An atom with less than the normal number of electrons is a positive ion (a cation), and an atom with one or more extra electrons is a negative ion (an anion).
3) Which element has the lowest electronegativity value?
A) F
B) Fr
C) Cr
D) Cl
Answer:
ur mom jk i would say fr
Explanation:
how adaptations in a bird's beak help them survive in their environment
Answer:
they can get food easily and they can pack the predators to help them with their safty!♥
1. Which of the following elements have atoms with a full shell of
valence electrons (1 point)
a. Lithium
b. Oxygen
c. Hydrogen
d. Neon
Answer:
The answer is neon.
Explanation:
Hope this helped Mark BRAINLEST!!!
(On the verge of tears)
Calculate the final molarity of a 20mL- 1.3M salt solution after it has been diluted with 100ml water. Use M1V1 =M2V2. Round up answer to
the hundredths. Include unit.
Answer: The final molarity of a 20mL- 1.3M salt solution after it has been diluted with 100ml water is 0.22 M
Explanation:
According to the dilution law,
[tex]M_1V_1=M_2V_2[/tex]
where,
[tex]M_1[/tex] = molarity of stock solution = 1.3 M
[tex]V_1[/tex] = volume of stock solution = 20 ml
[tex]M_1[/tex] = molarity of diluted solution = ?
[tex]V_1[/tex] = volume of diluted solution = (20+100) ml = 120 ml
Putting in the values we get:
[tex]1.3\times 20=M_2\times 120[/tex]
[tex]M_2=0.22M[/tex]
Therefore the final molarity of a 20mL- 1.3M salt solution after it has been diluted with 100ml water is 0.22 M
How many grams of potassium chloride are in 4.25 x 1023 molecules?
Do a quick conversion: 1 moles Potassium Chloride = 74.5513 gram using the molecular weight calculator and the molar mass of KCl.
Which of your recipes was the best?
Trial 1
Trial 2
Trial 3
Why is this your best recipe? What criteria did you meet?
Answer:
trial 1
Explanation:
trust
What is the mole fraction of KCI in an
aqueous solution that contains
26.3% KCI (weight/weight %)?
Molar Mass
KCI: 74.55 g/mol
H2O: 18.016 g/mol
Answer:
KCI
Explanation:
Convert 9.5 x 10^23
Q1 - How would you balance the following equation: N₂ + O₂ N₂O₅
A: N₂ + 5 O₂ N₂O₅
B: 2 N₂ + 5 O₂ 2 N₂O₅
C: N₂ + 5 O₂ N₂2O₅
D: N₂ + O₂ N₂O₅ (already balanced)
Q2 - In the reaction, HCl + NaOH NaCl + H₂O, what is/are the reactant(s)?
A: HCl only
B: HCl and NaOH
C: NaCl only
D: HCl and NaCl
nswer:
For Q1 its B!
Explanation:
cuz I'm smart dw.
10. If 3.5 kJ of energy are added to a 28.2 g sample of iron at 20°C, what
is the final temperature of the iron in kelvins? The specific heat of iron
is 0.449 J(g•K).
Answer:
569K
Explanation:
Q = 3.5kJ = 3500J
mass = 28.2g
∅1 = 20°C = 20 + 273 = 293K
∅2 = x
c = 0.449
Q = mc∆∅
3500 = 28.2×0.449×∆∅
3500 = 12.6618×∆∅
∆∅ = 3500/12.6618
∆∅ = 276.4220
∅2 - ∅1 = 276.4220
∅2 = 276.4220 + ∅1
∅2 = 276.4220 + 293
∅2 = 569.4220K
∅2 = 569K
When the temperature is increased, there is the increase in thermal energy of the system. The final temperature of the iron in kelvins is 570 K.
What is energy?The energy is the ability to do work.
Given is the energy Q = 3.5 kJ = 3500 J, mass of sample m = 28.2 g, specific heat of iron Cp = 0.449 J(g•K).
The initial temperature in kelvins is T1 = 20°C = 20 + 273 = 293K
The heat is related to the temperature difference as
Q = m c ∆T
Substitute the values into the expression,
3500 = 28.2 × 0.449 × ∆T
3500 = 12.6618 × (T2 -T1)
T2 - T1 = 276.4220
T2 = 276.4220 K +293 K
T2 = 569.4220K
The temperature of the iron is approximately 570 K.
Thus, the final temperature of the iron in kelvins is 570K.
Learn more about energy.
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The reaction between sodium and chlorine that forms table salt is shown
_Na(s) + Cl2 (g) → _NaCl (3)
What coefficient should be added to the blanks to balance the equation?
А.
2
В.
1
2.
2
Answer: 2 Na (s) + Cl(g) -> 2 NaCl (s)
Explanation:
The overall electrical charge on a stable element is_____
Answer: the answer is 0
Explanation:A stable atom has a net charge of 0. In other words, it has an equal number of protons and electrons. The positive protons cancel out the negative electrons.