Answer:
Explanation:
Nitrogen has an atomic number of 7 (Z=7) because it has 7 protons in its nucleus. Some nitrogen atoms have an atomic mass number of 15 (A=15). A is the number of neutrons plus protons in the nucleus. However, we already know that there are 7 protons.
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1) A 15.0 gram sample of sodium hydrogen carbonate, NaHCO3, was contaminated with an impurity. In order
to determine the purity of the sample, it was heated to decompose the material according to the following
reaction:
2NaHCO3 → Na2CO3 + H2O + CO2
If 6.35 grams of sodium carbonate, Na2CO3, were recovered, what percentage (by mass) of the sample was
sodium hydrogen carbonate, NaHCO3?
I
Answer:
67.1%
Explanation:
Based on the chemical equation, if we determine the moles of sodium carbonate, we can find the moles of NaHCO₃ that reacted and its mass, thus:
Moles Na₂CO₃ - 105.99g/mol-:
6.35g * (1mol / 105.99g) = 0.0599 moles of Na₂CO₃ are produced.
As 1 mole of sodium carbonate is produced when 2 moles of NaHCO₃ reacted, moles of NaHCO₃ that reacted are:
0.0599 moles of Na₂CO₃ * (2 moles NaHCO₃ / 1 mole Na₂CO₃) = 0.1198 moles of NaHCO₃
And the mass of NaHCO₃ in the sample (Molar mass: 84g/mol):
0.1198 moles of NaHCO₃ * (84g / mol) = 10.06g of NaHCO₃ were in the original sample.
And percent of NaHCO₃ in the sample is:
10.06g NaHCO₃ / 15g Sample * 100 =
67.1%HELP PLEASE, I NEED THIS BY TODAY!
If you have a 10 gram sample of uranium-235 how much would still be uranium-235 after 1407.6 million years?
Answer:
2.48 g
Explanation:
From the question given above, the following data were obtained:
Original amount (N₀) = 10 g
Time (t) = 1407.6 million years
Amount remaining (N) =?
Next, we shall determine the rate of decay (K) of uranium-235. This can be obtained as follow:
NOTE: Uranium-235 has a half life of 700 million years.
Decay constant (K) =?
Half life (t½) = 700 million years
K = 0.693/t½
K = 0.693/700
K = 9.9×10¯⁴ / year
Therefore, Uranium-235 decay at a rate of 9.9×10¯⁴ / year.
Finally, we shall determine the amount of Uranium-235 remaining after 1407.6 million years as follow:
Original amount (N₀) = 10 g
Time (t) = 1407.6 million years
Decay constant (K) = 9.9×10¯⁴ / year
Amount remaining (N) =?
Log (N₀/N) = kt /2.3
Log (10/N) = (9.9×10¯⁴ × 1407.6) /2.3
Log (10/N) = 0.60588
10/N = antilog (0.60588)
10/N = 4.04
Cross multiply
10 = 4.04 × N
Divide both side by 4.04
N = 10/4.04
N = 2.48 g
Therefore, 2.48 g of uranium-235 is remaining after 1407.6 million years.
If you have a 10 gram sample of uranium-235 there would still be uranium-235 after 1407.6 million years - 2.5 grams.
The half-life of U-235 is the time it takes for half the U to decay. We know that U-235 has 703.8 million years as its half-life which means it takes 703.8 million years to half of its initial amount.
After one half-life, half (50 %) of the original amount will remain. After a second half-life, half of that amount (25 %) will remain, and so on.We can construct a table as follows:
No. of Fraction Amount
half-lives t/(yr × 10⁶) remaining remaining/g
1 703.8 ½ 10/2 = 5
2 1407.6 ¼ 10/4 = 2.50
Thus, the correct answer is - 2.5 grams.
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4) If a snail averages about 0.0045 miles per hour (mi/hr), what is his average speed in meters per
second (m/s) (1 mile = 1.6 km)?
Answer:
the answer is 0.00201168 meters per second
Density of mercurio is
Answer:
The density of mercury is 13.6 g/mL, which is equal to 1360 kg/m3.
how many grams in 5mg
Answer:
0.005
Explanation:
I looked it up
Explanation: It's important to understand that "mg" is the abbreviation
for milligrams and "g" is the abbreviation for grams.
To convert 5 milligrams into grams, we first find the conversion factor
for milligrams and grams, which is 1,000 milligrams = 1 gram.
Next, notice that we're going from a smaller unit,
milligrams, to a larger unit, grams, so we divide.
Whenever we go from a smaller unit to a larger unit,
we will divide by the conversion factor.
So we have 5 mg ÷ 1,000.
When dividing by a power of 10, we can count the number of zeroes
in the power of 10 and move the decimal point that many places to the left.
So our answer is 0.005 grams.
Which statement explains how the bands in the crystal of a metal are like atomic orbitals?
A. They both have localized electrons that orbit specific atoms.
B. They both involve ionization of some atoms so bonding can occur.
C. They both have delocalized electrons that move from atom to atom.
D. They both allow electrons to move from lower energy levels to higher energy levels.
Answer:
D
Explanation:
Correct On EDU
Crystal lattice of metals are highly ordered in which the ions and electrons are arranged in a stoichiometric proportion. But,electrons can excite to higher energy levels as they fo in atomic state. Thus , option D is correct.
What is crystal lattice?Crystal are highly ordered structures of solids and is anisotropic in nature with a perfect geometry and crystal lattice units. There will be free electrons present in the interstices spaces and which can be delocalized throughout the lattice results in conduction.
Electrons can acquire energy to excite to the higher energy levels from the lower energy level in a crystal lattice. Electrons are revolving around the nucleus of an atom through definite circular paths of fixed energy.
Electrons in an atom tends to excite to higher energy levels and then will return to the lower energy level by emission of energy in the form of light or heat. This process make the element coloured and conducting as in the case of crystal bands in metals.
Hence, both atoms and metal lattice allow electrons to move from lower energy levels to higher energy levels and option D is correct.
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All elements on the periodic table are________
Answer:
Explanation:
arranged in order of increasing.
The law of conservation of energy states that energy can neither be created nor destroyed; however, if you stretch out a ball in your hand and let it freely drop, the ball will not quite bounce back up to the height you dropped it from. Which of the following best explains why this happens? *
The pull of gravity negates the law of conservation of energy.
Some of the energy has to be used up to push the ball back into the air, destroying it forever.
The ball falls too quickly, so the energy does not have enough time to fully recharge.
Some of the energy is released into the air as heat (thermal energy) due to friction.
which answer is it? help
Answer: the last one:)
Explanation: energy cannot be destroyed but can be transfered
(called energy transfer).
A regulation that should be followed to prevent accidents is called safety blank
Answer:
Safety Regulations
Explanation:
hope this helps:)
find the volume. mass is 9.75 g and the density is 15.6 g/cm3
Answer:
1.6cm3
Explanation:
density = mass/volume
15.6g/cm3= 9.75 g/volume
15.6/9.75 = volume
1.6cm3 = volume
An Olympic swimmer can swim a distance of 360m in 8.5 minutes. What is her speed?
Answer:
42.3529412 m/min or 0.705882353 m/s
Explanation:
We can calculate speed using the following formula.
[tex]s=\frac{d}{t}[/tex]
where [tex]d[/tex] is distance and [tex]t[/tex] is time.
The Olympic swimmer can swim 360 meters in 8.5 minutes. Therefore,
[tex]d= 360 \ m \\t= 8.5 \ min[/tex]
Substitute the values into the formula.
[tex]s=\frac{360 \ m}{ 8.5 \ min}[/tex]
Divide.
[tex]s= 42.3529412 \ m / min[/tex]
Her speed is 42.3529412 meters per minute.
If we want to find her speed in meters per second, convert the minutes to second.
1 minute is equal to 60 seconds, so we can multiply 8.5 by 60.
[tex]8.5 *60=510[/tex]
The swimmer can swim 360 meters in 510 seconds.
[tex]s=\frac{d}{t}[/tex]
[tex]d= 360 \ m \\t= 510 \ s[/tex]
[tex]s=\frac{360 \ m}{510 \ s}[/tex]
[tex]s=0.705882353 \ m/s[/tex]
Her speed is also 0.705882353 meters per second.
Betty drew the life cycle of a butterfly for a science exhibition. The life cycle showed the various stages of growth before the egg turns into a butterfly. What type of model did Betty use?
Answer:
Conceptual
Explanation:
A conceptual models are graphical representation of the biological or physical system or another natural phenomenon. It is helping people to understand, imitate and make connections with natural phenomena. The given situation is an example of a conceptual model because it is represented in a graphical way and represents the basic biological events of the actual transformation of a butterfly (transforming a young adult insect into a young adult worm).Answer:
Conceptual
letter B
Suppose you set a glass of water in direct sunlight for 2 hours and measure its temperature every 10 min . What type of graph would you use to display your data .
HELP ASAP PLS
Answer:
line graph
Explanation:
The type of graph would be used to display the data is line graph.
What is graph?Graph is defined as a visual representation, such as a picture or diagram, that shows information or values in a structured way. The graph's goal is to visually represent numerical data so that it can be quickly, simply, and clearly understood. As a result, graphs are visual displays of data.
Although a graphical display is easier to understand, data can also be presented as a table. For this kind of data, a line graph will be used. This will show more clearly how the temperature of the water fluctuates over the course of two hours. Time is an independent variable, whereas temperature is a dependent variable.
Thus, the type of graph would be used to display the data is line graph.
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5. If a block of wood has a density of 0.6 g/cm3 and a mass of 120 g, what is its volume? (D= M/V)
Answer:
200 cm^3
Explanation:
V = M/D
V = 120g / (0.6g/cm^3)
V = 200 cm^3
In this case, the volume is 200 cm^3.
What is density?
Density is defined as the mass of a material substance per unit volume. The equation for density is d = M/V, where d stands for density, M for mass, and V for volume. Grams per cubic centimetre are a typical unit of density measurement.
For instance, the density of Earth is 5.51 grammes per cubic centimetre, but the density of water is 1 gramme per cubic centimetre. Kg/m3 is another way to measure density (in metre-kilogram-second or SI units). For instance, the air has a density of 1.2 kilogrammes per cubic metre.
Textbooks and manuals provide lists of the densities of common solids, liquids, and gases. The mass of a body may be calculated from its volume using density, and vice versa. The mass is equal to the volume multiplied by the density (M = Vd), whereas the volume is equal to the mass divided by the density (V = M/d).
You may calculate a body's weight by multiplying its mass by the acceleration of gravity, which is typical of more practical significance than its mass. Additionally, there exist tables that indicate the weight of various substances per unit volume; this amount is sometimes referred to as specific weight, weight density, or unit weight.
Instead of referring to the density of a single particle, the term "particle density" refers to the number of particles per unit volume and is typically written as n.
Therefore, here the volume is 200 cm^3.
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trial 2, 2.68 g/cm/3 trial 3, 2.84g/cm/3. aluminum has a density of 2.70g/cm/3 calcute the percent error for each trial.
Answer:
trial 2: 0.74
trial 3: 5.19
I think but the equation for sloving percent error is:
(true value - determined value)/true value * 100
Explanation:
2000 km/sec. Convert that to
m/sec.
Answer:
2000 km/sec
1km=1000m
2000×1000
2000,000 m/sec
what happened to the color of the sand when it goes through filtration and is quantitative or qualitative
Answer:
Qualitative
Explanation:
I'm not sure if there was another part to the question, but if you are looking at the color of the sand, that is a qualitative observation.
Quantitative statements involve numbers. (Ex: The house has 4 bedrooms.) Qualitative statements describe characteristics. (Ex: The house is blue.)Round off the following quantities to the number of significant figures indicated in parentheses: 69.733 g (2)
Answer:
70
Explanation:
There are 5 significant figures in the problem. Since it has a decimal point, we start on the left hand side and work our way to the right. You would end up at 69, but then you have to round up since the next number is a 7, which is greater than or equal to 5.
_____________ dating places the rocks and rock layers in an area into sequential order. ________ dating gives an exact date on rock layers.
Geologic, Absolute
Relative, Geologic
Relative, Absolute
Time, Geologic
2) A wooden block has a volume of 176 cm3 and a density of 18.2 g/ cm3. What is the mass?
Answer:
3,203.2 g
Explanation:
density multiplied by volume gives you the mass, and both cm3 cancel eachother out so you are left with just g.
which statement describes redis experiment which helped disprove spontaneous generation?
Answer:
it is A i just got it right
Explanation:
Use your knowledge of atomic calculations to complete the chart.
Element
Protons
Neutrons
Electrons
Atomic
Number
3
15
Atomic
Mass
7
31
35
19
28
31
P
ci
Ni
K
Ag
H
39
19
-18
47
OK
1
1
14
14
06
3
Si
w
74
1010
Ne
10
10
Answer:
For hydrogen. H
Explanation:
Atomic number is 1
Proton number is 1
Mass number is 2
Neutron number is 1
How far is it from H to G?
Which of the samples pictured is most likely a nonmetal?
Answer:
c
Explanation:
Answer:
it is c because its a hard one and you should know what that is and it is a nonmetal even if not exactly its to be slightly
Explanation:
Bonnie wants to see if playing music to plants will help them grow taller. She buys 4 of the same kind of plant. They all receive the same amount of sun and water. She plays rap music to plant A, country music to plant B, rock music to plant C, and plant D gets no music at all. Everyday for a week she measures the height of each plant.
DO NOT HESITATE TP ASK FOR FURTHER EXPLANATION.
HOPE THAT HELPED.6.Think about where you live now or where you have lived in the past; use complete sentences to describe this environment and the weather. What building materials do you believe would work well to build a home in that area? Explain why you chose these materials.
Answer and Explanation:
I have always lived in the same region. The region where I live is flat and stable, the site has asphalt and the climate is tropical with a long summer and poorly defined seasons. My region does not have drastic changes and temperature and the climate is hot most of the year. For this reason, it is necessary to use materials that are thermal insulators, on the contrary we need to use materials that are not good thermal insulators such as concrete blocks, bricks, cement and ceramics, we will also need common tiles and rafters to support them.
From observing the plant and animal cell diagrams above, which cell seemed to have more of a regular structure?
Answer:
the green one
Explanation:
a table that compares the properties of suspensions, colloids, and solutions.
Answer:periodic table
Explanation:
Which are characteristics of all living things? Check all that apply. are made of cells need energy A. can breathe B. respond to stimuli C. can reproduce D.grow and develop / help me please
Answer:
All can be charactoristics of a living thing
Explanation:
Answer:
Grow
Need energy
respond to stimuli
are made of cells
Explanation:
correct on edge 2022 :)
Which of these is an extensive ?
A- density
B- melting point
C- temp.
D- volume