13 Elements within the same main groups (1-8)
Humans have 46 chromosomes. A human egg cell has.
O 23 chromosomes
O 46 chromosomes
O 92 chromosomes
Explanation:
23 each from parents....total 46..
NEED HELP!
C=46.67%, H=4.48%, N=31.10%, O=17.76%.
The molecular weight is 180.16g/mol.
Answer:
[tex]C_7H_8N_4O_2[/tex]
Explanation:
Hello!
In this case, since the determination of an empirical formula is covered by first computing the moles of each atom as shown below:
[tex]n_C=\frac{46.47g}{12g/mol}=3.9mol\\\\ n_H=\frac{4.48g}{1g/mol} =4.5mol\\\\n_N=\frac{31.10g}{14g/mol} =2.2mol\\\\n_O=\frac{17.76g}{16g/mol} =1.1mol[/tex]
Now, we divide each moles by the fewest moles (those of oxygen), to obtain the subscripts in the empirical formula:
[tex]C:\frac{3.9}{1.1}=3.5 \\\\H:\frac{4.5}{1.1}=4 \\\\N:\frac{2.2}{1.1} =2\\\\O:\frac{1.1}{1.1} =1[/tex]
Thus, the empirical formula, taken to the nearest whole subscript is:
[tex]C_7H_8N_4O_2[/tex]
Whose molar mass is 180.16, therefore the empirical formula is the same to the molecular one.
Best regards!
11. Which of the following is a characteristic of all chemical changes? *
Answer:
i think A
Explanation:
definitely not c
a new substance is not always formed, like when you burn a piece of paper.
i am stuck between a and b :(
How many moles are in 25.58 grams of H20? SHOW WORK
Answer:
1.42 moles
Explanation:
25.58 g of H₂O .
Molecular weight of water = 2 x 1 + 16 = 18
1 mole of water = 18 g of water
18 g of water = 1 mole
25.58 g of water = 25.58 / 18 mole
= 1.42 moles .
Pb(NO3)2+K2CrO4=PbCrO4+KNO3 reaction type
The reaction between Pb(NO₃)₂ (lead(II) nitrate) and K₂CrO₄ (potassium chromate) can be classified as a double displacement or precipitation reaction.
In this reaction, the lead(II) ion (Pb²⁺) from Pb(NO3)2 combines with the chromate ion (CrO₄²⁻) from K₂CrO₄ to form lead(II) chromate (PbCrO₄). Meanwhile, the potassium ion (K⁺) from K₂CrO₄ combines with the nitrate ion (NO₃⁻) from Pb(NO₃)₂ to form potassium nitrate (KNO₃).
The balanced chemical equation for the reaction is:
Pb(NO₃)₂ + K₂CrO₄ → PbCrO₄ + 2KNO₃
In this equation, the subscripts and coefficients are used to balance the number of atoms on each side of the equation to satisfy the law of conservation of mass.
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1. 2.0 mL/s x 4.0 hrs = ? L
How do you do this conversion problem
Answer:
29 L.
Explanation:
Hello!
In this case, considering that we are performing a conversion by which the time should be cancelled out to obtain liters, we first need to convert the seconds on bottom to hours and then the volume on top to liters, just a shown down below:
[tex]2.0\frac{mL}{s} *\frac{1L}{1000mL} *\frac{3600s}{1hr}*4.0hr\\\\=28.8L[/tex]
Which turns out 29 L with 2 significant figures.
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helpo pls rnn only have 5 min
The percent
composition of an
unknown substance is
75.42 % Carbon, 6.63
% Hydrogen, 8.38 %
Nitrogen, and 9.57 %
Oxygen. If its molar
mass is 668.0 g/mole
what is its molecular
formula?
Answer:
mass of the empirical formula is 259.64 g/mol. = 519 g/mol
Explanation:
The molecular formula is Hg2C4H6O4. One of the most deadly poisons, strychnine, has a formula weight of 334 g/mol and the composition 75.42% C, 6.63% H, 8.38% N; the rest is oxygen.
Use the atomic masses of the elements to determine the percent composition by mass of sodium and chlorine in sodium chloride.
Answer:
Explanation:
Percent composition of sodium chloride .
NaCl
Mol weight = 23 + 35.5 = 58.5 g
58.5 g of NaCl contains 23 g of Na
100 g of NaCl contains 23 x 100 / 58.5 g of Na
= 39.3 %
Na = 39.3 %
58.5 g of NaCl contains 35.5 g of Cl
100 g of NaCl contains 35.5 x 100 / 58.5 g of Na
= 60.7 %
Cl = 60.7 % .
please i need it Lab: Calorimetry and Specific Heat
Answer:
step3:
aluminum- 11.98
copper-12.14
iron- 12.31
lead- 12.46
step5: 12.46, 52.31, 39.85
step7: 100, 22.4, 27.1, 4.7, 72.9
step5: 12.26, 52.49, 40.13
step7: 100, 22.7, 24.6, 1.9, 75.4
step5: 12.42, 52.66, 40.24
step7: 100, 22.5, 24.9, 2.4,75.1
step5: 12.34, 51.99, 39.65
step7: 100, 22.6, 23.3, 0.7, 76.7
step8: 0.90,0.35,0.44,0.12
After a reaction went to completion, the crude reaction mixture consisted of two compounds, A and B, which were isolated by extraction. After each compound was dried, their masses were found to be, 117 mg of compound A and 89 mg of compound B. Both compounds were individually recrystallized and weighed again. After recrystallization, the mass of compound A was 93 mg and the mass of compound B was 83 mg. Calculate the percent recovery from recrystallization for both compounds
Answer:
See explanation
Explanation:
Mass of impure compound A = 117 mg
Mass of impure compound B = 89 mg
Mass of pure compound A = 93 mg
Mass of pure compound B = 83 mg
Percentage recovery of pure compound A = 93 mg/117 mg * 100 = 79.5 %
Percentage recovery of pure compound B = 83mg/89 mg * 100/1 = 93.3 %
are cation often ligand in complex ?
Answer:
To name a coordination compound, no matter whether the complex ion is the cation or the anion.
Explanation:
How much of a 500 gram sample of potassium-42 is left after
62 hours? The half-life of K-42 is 12.4 hours?
Answer:
The correct answer is - 15.625
Explanation:
The half-life is the time it takes to decay half value or quantity of its initial quantity or value. It is given that,
The half-life of K-42 = 12.4 hours
The initial value of K-42 = 500 gm
After 62 hours the value of k-42 = ?
The number of half cycle = 62*1/12.4 = 5,
therefore it will have 5 half-lives
initial - 500
1st half life - 500/2 = 250
2nd - half life - 250/2 = 125
3rd half life - 125/2 = 62.5
4th half life - 62/2 = 31.25
fifth half life - 31.25/2 = 15.625
Thus, the correct answer is =15.625g
15.625 g of a 500 gram sample of potassium-42 with 12.4 hours of Half -life is left after 62 hours.
The half-life is the time after which half of the initial quantity of a radioactive substance is left .
Given here,
The half-life of K-42 = 12.4 hours
The initial quantity of K-42 = 500 gm
The final quantity after 62 hours = ?
The number of half cycle
[tex]\bold { = 62\times \dfrac 1{12.4} = 5,}[/tex]
Thus the number of half life cycles in 62 hours is 5,
After 1 half life [tex]\bold {= \dfrac {500}{2} = 250}[/tex]
After 2 half lives [tex]\bold {= \dfrac {250}{2} = 125}[/tex]
After 3 half lives [tex]\bold {= \dfrac {125}{2} = 62.5}[/tex]
After 4 half lives [tex]\bold {= \dfrac {62.5}{2} = 31.25}\\[/tex]
After 5 half lives [tex]\bold {= \dfrac {31.25}{2} = 12.625}\\[/tex]
15.625 g of a 500 gram sample of potassium-42 with 12.4 hours of Half -life is left after 62 hours.
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Describe what an alchemist does
A recipe for spaghetti souce requires 2.5 cups of tomato sauce. If only metric measures are available, how many milliliters of tomato sauce are needed?(1qt = 4 cups, 1q = 946 mL)
Answer:
591.25ml
Explanation:
4 cups=946ml
0.5cups=946÷8=118.25ml
2.5cups=118.25ml*5=591.25ml
19. Which of the following has 3 significant figures? 0.0730 O 300 4003
Answer:
0.0730
Explanation:
decimal 0s don't count except for ones at the end
All the following process lead to a decrease in salinity of seawater except for A. melting of sea Ice B. Precipitation C. runoff D. evaporation
Which object represents a heterogeneous mixture?
A. Brass key
B. Metal rings
C. Aluminum pans
D. Steel wool
The heterogenous mixture among the following is steel wool because, steel is made of metal iron with the traces of carbon and other metals such as chromium, copper, nickel etc.
What is steel?Steel is an alloy made of iron strengthened with carbon. Steel is an essential alloy in industrial fields as well as in house holds. Most of the potteries and now made of steel. Steel is harder, resistant to chemical and corrosion and microbes.
A mixture is a combination of two or more components. A homogenous mixture is the one where all the components form a single phase without separation. For example salt solution.
Heterogenous mixtures are those, in which the individual components are in separate phases. Steel contains metals along with carbon and steel wool is a combination of cotton and the solid metal. Thus option D is correct.
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Why is it necessary for the radio of atoms to be expressed as the distance between the nuclei of the two identical atoms bonded together?
Which best describes the three general groups of elements?
Answer:
D
Explanation:
What does an electric field
surround?
Answer:
An electric field is the physical field that surrounds each electric charge and exerts force on all other charges in the field, either attracting or repelling them.
Why the copper is able to replace the silver, but the reverse reaction will not result in a replacement reaction?
Answer:
Copper is more reactive and higher in the activity series
Explanation:
Copper is able to replace the silver in a replacement reaction because it is more reactive and higher in the activity series.
Substances or ions that are higher in the activity series are typically more reactive than those ones below them.
In like manner, they are able to replace the lowers ones in a chemical reaction due to their higher reactivity potential.
A less reactive element and a lower one in the activity series cannot displace a higher one in the series.
Nitrogen forms more oxides than any other element. The percents by mass of N in three different nitrogen oxides are (I) 46.69%; (II) 36.85%; (III) 25.94%. For each compound, determine (a) the simplest whole-number ratio of N to O, and (b) the number of grams of oxygen per 1.00 g of nitrogen.
Answer:
[1]. NO; 1.14 g,
[2]. N₂O₃; 1.71 g,
[3]. N₂O₅; 2.86 g.
Explanation:
[1]. For the first oxide, there is 46.69% of Nitrogen and [100 - 46.69%] of Oxygen, that is 53.31% of oxygen. The simplest whole-number ratio of N to O = [46.69/14.01] ÷ [53.31/ 16] = 3.33/3.33 = 1 : 1.
Hence, Nitrogen =1 and oxygen is 1, the compound = NO.
The number of grams of oxygen per 1.00 g of nitrogen for this compound is calculated as below:
The number of grams of oxygen per 1.00 g of nitrogen for this compound = (1/ 0.4669) - 1 = 2.14 - 1 = 1.14 g.
[2]. For the second oxide, there is 36.85% of Nitrogen and [100 - 36.85%] of Oxygen, that is 63.15% of oxygen. The simplest whole-number ratio of N to O = [36.85/14.01] ÷ [63.15/ 16] = 2.63/3.94 = 1 : 1.5.
Hence, Nitrogen =1 and oxygen is 1.5. There is need to change it to whole number, therefore, when it is multiplied by 2, it gives 2:3. Therefore, the compound = N₂O₃.
The number of grams of oxygen per 1.00 g of nitrogen for this compound is calculated as below:
The number of grams of oxygen per 1.00 g of nitrogen for this compound = (1/ 0.3685) - 1 = 2.71 - 1 = 1.71 g.
(3). For the third oxide, there is 25.94% of Nitrogen and [100 - 25.94%] of Oxygen, that is 74.06% of oxygen. The simplest whole-number ratio of N to O = [25.94/14.01] ÷ [74.06/ 16] = 1.85/4.63= 1 : 2.5.
Hence, Nitrogen =1 and oxygen is 2.5. There is need to change it to whole number, therefore, when it is multiplied by 2, it gives 2:3. Therefore, the compound = N₂O₅.
The number of grams of oxygen per 1.00 g of nitrogen for this compound is calculated as below:
The number of grams of oxygen per 1.00 g of nitrogen for this compound = (1/ 0.2594) - 1 = 3.86 - 1 = 2.86 g
Please help and try to explain if you can!
Answer: 4.76 * 10^2
476.
you bring the ending decimal to the first number and it takes you two hops to get the first number so that's what you put in the box after the 10
What part of the underside of a gecko's feet
allows it to stick to surfaces?
O cilia
O heat
O pillars
O webbing
Answer:
it was pillars
Explanation:
i guessed and it was right LOL
Answer:
O pillars
Explanation:
Right on EDGE 2021
Help!! Ilgive brainliest
Balance the following equation: AlCl3+Mg-> MgCl2+Al
Answer:
Aluminum Chloride+Magnesium=Magnesium Chloride+Aluminum
How many grams of copper (II) fluoride (CuF2) are needed to make 9.66 liters of a 2.73 M
solution?
Mass of Copper (II) fluoride needed = = 2677.87 g
Further explanationGiven
9.66 L of 2.73 M Copper (II) fluoride
Required
Mass
Solution
Molarity : mol solutes per liters of solution
M = n : V
n = mol solute
V = volume of solution
mol Copper (II) fluoride :
= M x V
= 2.73 M x 9.66 L
= 26.3718 mol
Mass Copper (II) fluoride :
= mol x MW CuF₂
= 26.3718 mol x 101,543 g/mol
= 2677.87 g
Read the descriptions below of two substances and an experiment on each. Decide whether the result of the experiment tells you the substance is a pure substance or a mixture, if you can.
Sample A is of a coarse grey powder with a faint unpleasant smell. of the powder is put into a funnel lined with a sheet of thick paper. Distilled water is poured slowly over the powder. Most of the powder disappears, but of a gritty black sand-like material is left on the surface of the paper. Pouring more water over the black material doesn't change how much of it there is.
Sample B is a solid yellow cube with a total mass of 50.0 g. The cube is put into a beaker filled with 250. mL of water. The cube collapses into a small pile of orange powder at the bottom of the beaker. When this powder is filtered out, dried and weighed, it has a total mass of 29.9 g. If the experiment is repeated with 500. mL of water, the powder that's left over has a mass of 10.0 g.
Answer:
Sample A - mixture
Sample B- Mixture
Explanation:
Looking at sample A, we can see that as water was poured over sample A, the sample was separated into its components as the powder disappeared leaving behind a gritty black sand-like material on the surface of the paper. A separation of the mixture has taken place.
In sample B, we can clearly see that it is a mixture because the amount of solid recovered is much less than the total mass of the solid put into the beaker. The sample must have been separated into its components.
I WILL GIVE BRAINLTIST THING OR WHATEVER IT'S CALLED
Which of the following objects would have the greatest gravitational attraction between them if they were set 3.0 km apart?
A .20kg object and a 200kg object
A 10kg object and a 100kg object
A 30kg object and a 200,000kg object
A 400,000 kg object and a 100,000,000kg object
Answer:
A 400,000 kg object and a 100,000,000kg object
Explanation:
The objects with the most mass between them will have the greatest gravitational attraction.
This is why the last option is the right choice.
The reason for this is based on the Newton's law of universal gravitation which states that:
"the gravitational force of attraction between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them".
So, the more the mass, the greater the gravitational attraction between two bodies.
