Explanation:
The reason why stars are so important is that they have helped humans navigate through Earth. When it was dark these stars would light up the sky giving people lightly. In addition, stars are very important because they make life on Earth. ... Earth would just be a rock with ice.
An element is shiny, conducts heat and electricity, and has 2 valence electrons. Which element could this be?
a.Na
b.Fe
c.O
d.Ca
A ______ in medicine is a form of scientific argumentation in which evidence is used to rule out claims and support the best conclusion.
fill in the blank
Answer: Scientific reasoning
Explanation:
A scientific reasoning can be defined as the justification which connects the evidence with that of the claim and it rules out all those claims that are not supported by any evidence. It explains the fact that how evidence can support a claim and scientifically acceptable conclusion can be drawn. An argument is always based on one or more claims which can either be true or evidentially proved.
A mixture of He, Ne, and Ar has a pressure of 14.9 atm at 28.0 °C. If the partial pressure of He is 1.43 atm and the partial pressure of Ar is 4.45 atm, what is the partial pressure of Ne?
Answer: The partial pressure of Ne is 9.02 atm.
Explanation:
Given: Total pressure = 14.9 atm
Partial pressure of He = 1.43 atm
Partial pressure of Ar = 4.45 atm
Partial pressure of Ne = ?
According to the Dalton's law of partial pressures the total pressure exerted by the a number of gases in a mixture is equal to the sum of partial pressures of each gas present in the mixture.
Now, for the given mixture the partial pressure of Ne is as follows.
Total pressure = Partial pressure of He + Partial pressure of Ar + Partial pressure of Ne
Substitute the values into above formula as follows.
Total pressure = Partial pressure of He + Partial pressure of Ar + Partial pressure of Ne
14.9 atm = 1.43 atm + 4.45 atm + Partial pressure of Ne
Partial pressure of Ne = 14.9 atm - 5.88 atm
= 9.02 atm
Thus, we can conclude that the partial pressure of Ne is 9.02 atm.
if irons temp goes from 50c to 75c in a 20g sample how many joules of heat were used
Answer:
224.5J
Explanation:
Using the formula as follows:
Q = m × c × ∆T
Where;
Q = amount of heat (J)
m = mass of substance (g)
c = specific heat capacity.
∆T = change in temperature (°C)
According to this question;
m = 20g
∆T = 75°C - 50°C = 25°C
Q = ?
c of iron = 0.449 J/g°C
Using Q = m × c × ∆T
Q = 20 × 0.449 × 25
Q = 224.5J
you had a 5 gram sample , how much of the original substance would remain after 1 half- life?
what is the half life though?
If you diluted 120 mL of 1,049 M NaCl to 1,920 mL, what would
be the new concentration of NaCl? Don't put units into your
answer.
Answer:
65.56 M
Explanation:
Using the formula as follows:
C1V1 = C2V2
Where;
C1 = initial concentration (M)
C2 = final concentration (M)
V1 = initial volume (L)
V2 = final volume (L)
According to the information in this question,
C1 = 1,049 M
C2 = ?
V1 = 120 mL
V2 = 1,920 mL
Using C1V1 = C2V2
1049 × 120 = C2 × 1920
125880 = 1920C2
C2 = 125880 ÷ 1920
C2 = 65.56 M
How many atoms are in 1.204x10^22 moles of arsenic?
Answer:
0.02 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
We have
[tex]n = \frac{1.204 \times {10}^{22} }{6.02 \times {10}^{23} } \\ = 0.02[/tex]
We have the final answer as
0.02 molesHope this helps you
Which wave has the highest frequency?
1
2
3
4
no link or i will report
Answer:
4
Explanation:
because number 4 moves continuous
How much 0.05 M HCl solution can be made by diluting 2L of 10 M HCl?
Answer:
400 L
Explanation:
As this problem deals with a dilution process, we can use the following formula:
C₁V₁=C₂V₂Where subscript 1 stands for the concentrated concentration and volume, while 2 stands for the diluted values. Meaning that in this case:
C₁ = 10 MV₁ = 2 LC₂ = 0.05 MV₂ = ?We input the data:
10 M * 2 L = 0.05 M * V₂And solve for V₂:
V₂ = 400 LUse the following periodic table to identify the letter(s) that match each of the statements below.
(Each element may be used once, more than once or not at all)
Answer:
l and t
Explanation:
because they are in group one
Answer:
L & T
since are found in the same group.
For the reaction CH3COOH→CH3COO– + H+, which statement is true?
CH3COOH is a Brønsted-Lowry base.
CH3COO– is an Arrhenius base.
CH3COOH is a Brønsted-Lowry acid.
CH3COO– is a Lewis base.
Answer:
For the reaction CH3COOH→CH3COO– + H+
Among the given statements which is the correct statement?
CH3COOH is a Brønsted-Lowry base.
CH3COO– is an Arrhenius base.
CH3COOH is a Brønsted-Lowry acid.
CH3COO– is a Lewis base.
Explanation:
Bronsted acid is the proton donor.
Bronsted base is the proton acceptor.
Arrhenius base is the one that releases OH- ions when dissolved in water.
Lewis base is the one that is an electron-pair donor.
In the given reaction,
CH3COOH→CH3COO– + H+
Acetic acid releases a proton.
So, it is a proton donor.
Hence, It is a Bronsted-Lowry acid.
Third option is the correct answer.
.
Determine the temperature of .084 moles of CO2 gas at 790 mmHg
which occupies a volume of 2.1L
Answer:
Explanation:
Molar volume at STP = 22.4L
So 0.084 mole of CO2 at STP has volume of 22.4*0.084 = 1.882L
Combined Gas Law: P1V1/T1 = P2V2/T2
760*1.882/273 = 790*2.1/Temperature
Temperature = 790*2.1*273/760/1.882
= 316.6K
PLS HELP ASAP NO LINKS WILL MARK BRAINLIEST IF CORRECT
What is the toxic life of nuclear waste?
10,000 years
100,000 years
100 years
1 million years
Answer:Strontium-90 and cesium-137 have half-lives of about 30 years (half the radioactivity will decay in 30 years). Plutonium-239 has a half-life of 24,000 years. High-level wastes are hazardous because they produce fatal radiation doses during short periods of direct exposure.
Explanation:
In comparison to other toxic industrial waste, nuclear waste is neither exceptionally dangerous nor difficult to manage. It is technically possible to dispose of high-level radioactive waste safely. The toxic life of nuclear waste is 10,000 years. The correct option is B.
Waste is no longer dangerous if radioactive material has adequately decomposed. However, it will take the radioactive material between a few hours and hundreds of millions of years to decay.
Breeder reactors produce plutonium-239, which has a half-life of 24,400 years and is exceedingly hazardous in even minute amounts. Cesium-137 and strontium-190 are low-level radioactive wastes from typical nuclear power facilities.
Thus the correct option is B.
To know more about nuclear waste, visit;
https://brainly.com/question/10501353
#SPJ6
please help i need this like in the next 5 minutes
it is the second one
how long ago did the Atlantic Ocean separate Canada from Ireland....plz answer I have no idea lol
Answer:
Around 150 million years ago
Explanation:
The Atlantic ocean was formed during the Jurassic period
Answer:
200 millon years ago
Explanation: please give me brainliest
What is the molarity of an aqueous solution containing 1.5 moles of calcium chloride in 2.75 L of solution? A. 0.004 M B. 0.55 M C. 1.83 M D. 4.13 M
Answer:
B. 0.55 M
Explanation:
Step 1: Given data
Moles of calcium chloride (solute): 1.5 molVolume of solution: 2.75 MStep 2: Calculate the molarity of the aqueous solution
The molarity is a way to express the concentration of a solution. It is equal to the quotient between the moles of solute and the liters of solution.
M = moles of solute / liters of solution
M = 1.5 mol / 2.75 L = 0.55 mol/L = 0.55 M
2 Na + Cl ---> 2NaCl
how many grams of NaCl can be produced if 33 grams of Na reacts with excess Cl2 and STP?
a. 170 g
b. 120 g
c. 84 g
d. 72 g
If 65 grams is ACTUALLY produced, what is the percent yield of NaCl in the above problem?
a. 54.2%
b. 38.2%
c. 77.4%
d. 90.3%
Answer:
1. d. 84g
2. c. 77.4%
Explanation:
1. Based on the reaction 2 moles of Na produce 2 moles of NaCl.
The moles of Na (22.99g/mol) in 33g are:
33g * (1mol / 22.99g) = 1.435 moles Na = 1.435 moles NaCl must be produced.
The mass of NaCl is (Molar mass: 58.44g/mol):
1.435moles * (58.44g / mol) = 84g
d. 84g
2. Percent yield is defined as 100 times the ratio between actual yield (65g) and theoretical yield (84g). The percent yield is:
65g / 84g * 100 =
c. 77.4%
Please help!!!! Best answer will get brainliest.
Answer:
ionic
Explanation:
I don't know if this correct
Which component is reduced during the electrolysis of brine?
A. sodium ions
B. chloride ions
C. water
D. sodium hydroxide
Answer:
During the electrolysis, hydrogen and chloride ions are removed from solution whereas sodium and hydroxide ions are left behind in solution. This means that sodium hydroxide is also formed during the electrolysis of sodium chloride solution.
Answer:
water....
Explanation:
gradpoint
22.5 g of silver nitrate reacts with excess magnesium bromide, determine the mass
of magnesium nitrate that will be produced.
Answer:
9.82 g of Mg(NO₃)₂
Explanation:
Let's determine the reaction:
2AgNO₃ + MgBr₂ → Mg(NO₃)₂ + 2AgBr
2 moles of nitrate silver reacts with MgBr₂ in order to produce 1 mol of magnesium nitrate and silver bromide.
We determine the moles of AgNO₃
22.5 g . 1mol / 169.87g = 0.132 moles
Ratio is 2:1.
2 moles of silver nitrate can produce 1 mol of magnesium nitrate
Then, our 0.132 moles may produce (0.132 . 1)/ 2 = 0.0662 moles
We convert moles to mass:
0.0662 mol . 148.3 g/ mol = 9.82 g
You have three solutions of aqueous Sodium hydroxide. Their concentrations are 0.5M, 1.0M, and 1.5M. Which solution has the weakest concentration?
Answer:
0.5 M has the weakest concentration.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to remember that the concentration, or molarity, of a solution is given in terms of moles per liters of solution.
In such a way, we can infer that the solution with the weakest concentration is the one with the smallest molarity, that is 0.5 M.
Best regards!
In the heating curve of an unknown substance, the line labeled C represents what change(s)?
A) Temperature
B) Kinetic Energy
C) Temperature and Kinetic Energy
D) Temperature and Potential Energy
Answer:
C) Temperature and Kinetic Energy.
Explanation:
Hello there!
In this case, according to the generic heating curve on the attached file, it possible to see that on the point C, whereas the line is diagonal, the temperature increases, but also the kinetic energy increases because the molecules gain energy due to the increase of the temperature. It is important to say that on flat lines, like those on B and D, the phase change takes place and just the potential energy change.
In such a way, we infer that the answer is C) Temperature and Kinetic Energy.
Best regards!
Answer:
C) Temperature and Kinetic Energy.
Explanation:
In the heating curve of an unknown substance, the line labeled C represents Temperature and Kinetic Energy.
Can someone give me an example of a synthesis reaction that is NOT a redox reaction? Pls don't send links. Thanks
Well an example is how hydrogen and oxygen react to form water, you could use that. We know that when two nonmetals react more than one product is possible. Sulfur and oxygen react to form sulfur dioxide or sulfur trioxide.
Hope this helps.
Determine the mass of MgCl2 needed to create a 100. ml solution with a concentration of 3.00 M.
Explanation:
[tex]1000ml \: contain \: 3 \: moles \\ 100 \: ml \: will \: contain \: ( \frac{100 \times 3}{1000} ) \: moles \\ = 0.3 \: moles \\ RFM = 95 \\ 1 \: mole \: weighs \: 95 \: g \\ 0.3 \: moles \: weigh \: ( \frac{(0.3 \times 95)}{1} \: g \\ = 28.5 \: g \: of \: magnesium \: chloride[/tex]
Given the general reaction: A+B → C. When 1 mole of A
reacts, 15 kJ of heat energy is released. What happens if 3
moles of A completely reacts?
a5 kJ of heat is released.
b 45 kJ of heat is released.
C 15 kJ of heat is released.
d There is not enough information.
Answer:
B. 45kg
Explanation:
3 x 15= 45
bicarbonato es metal o no?
Answer:
La palabra bicarbonato es un término químico para referirse a una sal ácida del ácido carbónico en combinación con un metal. ... Pero si sólo está sustituido un átomo de hidrógeno por el metal, entonces obtenemos un bicarbonato o carbonato ácido, por ejemplo, bicarbonato sódico: CO3H Na.
Convert 5.0 g H2 to liters at STP
Answer:
2.6 L CO2 at STP
Explanation:
sorry if its wrong!
O nióbio é um metal encontrado em jazidas naturais, principalmente na firma de óxidos. Em uma jazida que contenha nióbio com número de oxidação +5, a formula do óxido predominante desse metal corresponde a:
Answer:
what
Explanation:
zA 25.0 mL sample of an acetic acid solution is titrated with a 0.175 M NaOH solution. The equivalence point is reached when 12.5 mL of the base is added. The concentration of acetic acid in the sample was ________ M. A 25.0 mL sample of an acetic acid solution is titrated with a 0.175 M NaOH solution. The equivalence point is reached when 12.5 mL of the base is added. The concentration of acetic acid in the sample was ________ M. 0.365 0.119 0.0875 0.175 none of the above
Answer:
0.0875M of Acetic Acid
Explanation:
Based on the reaction of acetic acid (HX) with sodium hydroxide (NaOH):
HX + NaOH → NaX + H₂O
1 mole of acetic acid reacts with 1 mole of NaOH
That means the moles of sodium hydroxide added = Moles the acetic acid at the equivalence point.
To solve this question we have to find the moles of NaOH = Moles HX. With the moles and the volume (25.0mL = 0.0250L) we can find the molarity of the acetic acid:
Moles NaOH = Moles Acetic acid:
12.5mL = 0.0125L * (0.175mol / L) = 0.00219 moles Acetic Acid
Molarity acetic acid:
0.00219 moles Acetic Acid / 0.0250L =
0.0875M of Acetic AcidConvert 2.3 atm to psi
Answer:=33.8 psi
Explanation:
Answer:
33.8007 (i think)
Explanation: