Answer:
Unless you mistyped the question, the answer should be 25+
Hurry up as fast as possible Ill mark you brainlist
It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms.
These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe. Present observations suggest that the first stars formed from clouds of gas around 150–200 million years after the Big Bang. Heavier atoms such as carbon, oxygen and iron, have since been continuously produced in the hearts of stars and catapulted throughout the universe in spectacular stellar explosions called supernovae.
The maximum allowable concentration of Pb2+ ions in water in a local community is 1.51 x 10-8 M. Could a chemist use 2.00 mL of 0.12 M KBr solution on a 5.00 mL sample of tap water to prove through a precipitation reaction that the water supply is safe? Show all work and reasoning
Answer:
The water supply is not safe.
Explanation:
Ionically, the reaction is;
Pb^2+(aq) + 2Br^-(aq) -------> PbBr2(s)
Amount of Br^- reacted = 2/1000 * 0.12 = 2.4 * 10^-4 moles
From the reaction equation;
1 mole of Pb^2+ requires 2 moles of Br^- for complete precipitation
x moles of Pb^2+ requires 2.4 * 10^-4 moles of Br^-
x = 1 * 2.4 * 10^-4 /2
x = 1.2 * 10^-4 moles of Pb^2+
Concentration of Pb^2+ precipitated from 5ml of tap water = 1.2 * 10^-4 * 1000/5
Concentration = 2.4 * 10^-2 M
The amount of Pb^2+ found in the water is greater than the maximum allowable concentration of Pb2+ ions in water in a local community which is 1.51 x 10-8 M. Therefore, the water supply is not safe.
Explain how cross cutting principles (intrusions, inclusions, faults) help to determine the relative age of a rock layer.
Answer:
The principle of cross-cutting relationships states that a fault or intrusion is younger than the rocks that it cuts through. ... So the fault must be the youngest formation that is seen. The intrusion (D) cuts through the three sedimentary rock layers, so it must be younger than those layers
Explanation:
Many plants in rainforests have leaf tips that come to a point, so precipitation drains off the leaf. This helps to keep the plant safe from harmful germs. Based on this info, what resource is prevalent in a rainforest?
Answer:
rainfall/water
Explanation:
The possession of drip tips by the leaves of plants in the rainforest is a form of adaptation against high rainfall. Without the drip tips on leaves, water will persist on the surface of leaves, and in conjunction with the warm climate, promotes the growth of pathogens such as fungi and bacteria.
Hence, the possession of drip tips on leaves is an indication of the prevalence of water in the rainforest region.
A whale is swimming in the ocean. It communicates with another whale by sending out a sound. Which of the following best
describes how the sound gets to the other whale?
A.
All of the sound absorbed by water changes to heat before getting to the other whale.
В.
The sound is transmitted through water until it reaches the other whale.
C.
All of the sound is diffused in
the water until only a faint sound reaches the other whale.
.D
The sound is reflected in the water before it gets to the other whale.
Answer:
A.
The sound is transmitted through water until it reaches the other whale.
Explanation:
When one whale makes a sound, the sound is transmitted through water until it reaches the other whale. The sound causes a ripple-like effect in the water, producing waves that travel in the water. The waves are heard in all directions. This is why humans can hear the sounds animals make underwater.
The statement which best describes how the sound gets to the other whale is that all of the sounds absorbed by water change to heat before getting to the other whale. Thus, the correct option for this question is A.
How sound may transmit from one place to another?The transmission of sounds is generally carried out through a medium in the form of waves. These sound waves involve the pattern of disturbance caused by the movement of energy.
In an aquatic environment, when one whale successfully constructs a sound, the sound is effectively transmitted through the medium that is known as water.
It remains in the form of waves until it reaches the other whale. The sound in a waveform provokes a ripple-like effect in the water and travels in the water. The waves are effectively heard in all directions.
Therefore, the correct option for this question is A.
To learn more about Transmission of sound in water, refer to the link:
https://brainly.com/question/18451537
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The energy that plants need for photosynthesis comes from
OA.
minerals,
OB. sunlight
OC.
oxygen
OD.
water.
Answer:
OB sunlight
Explanation:
it grows with it
whether the solution is acidic or basic And how much if we dissolve 6 grams of nitric acid and make 500cm3 of solution helpp pleasee
Answer:
i have no clue good luck
Explanation:
Need help. Is this correct
Answer:
Yes, that is correct!
Explanation:
Answer:
Yes
Explanation:
A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms. These electrons are simultaneously attracted by the two atomic nuclei. A covalent bond forms when the difference between the electronegativities of two atoms is too small for an electron transfer to occur to form ions.
How do you know if a compound is covalent
Answer:
Compounds containing two elements (binary compounds) can either have ionic or covalent bonding. If a compound is made from a metal and a non-metal, its bonding will be ionic. If a compound is made from two non-metals, its bonding will be covalent.
I GIVE BRAINLIEST IF YOU ANSWER!
Which of these is a characteristic of warm air? (5 points)
a It transfers energy through radiation.
b Its molecules are far apart.
c It sinks due to convection.
d It cools the land below i
Answer:
B.
Explanation:
The air molecules of warm air has higher energy. It causes them to move away from each other
A rectangular box has the following dimensions on the inside: 5 cm x 5 cm x 10 cm. What volume can the box hold, in milliliters?
- 20 mL
- 259 mL
- 25 mL
- 50 mL
Answer:
The volume in milliliters is 250mL
Explanation:
The volume of a rectangle is obtained using the equation:
Volume = Length * Width * Height
In the problem, we can take length as 5cm, width as 5cm and height as 10cm. Thus, volume of the rectangular box is:
Volume = 5cm * 5cm * 10cm
Volume = 250cm³
1mL = 1cm³.
That means the volume in milliliters is 250mL
atomic concept map. help me fill this out with the terms on the right. 40 points.
Answer:
can you like number them please? it would make it a lot easier
Explanation:
Which of the following is an example of a decomposition reaction?
What do both plants and animal cells break down for energy?
Answer:
both plant and animal cells must break down food molecules to get energy from them
Please Help! I Really Really Need It!
Answer:
The picteure isnt lodeing
Explanation:
mark brainly
Protons + Neutrons =
Answer:
mass
Explanation:
Give an example of a trait and explain how a genetic trait is passed down from
parent to offspring in animals.
Your answer
Explanation:
Parents pass characteristics such as hair color, nose shape, and skin color to their offspring. Not all of the parents' characteristics will appear in the offspring, but the characteristics that are more likely to appear can be predicted.
I'm just trying to answer questions. T^T
boron phosphite
Formula please help fast please please help me please please help
Answer: The formula for boron phosphite is BP
Explanation:
The answer would be BP
Hope this helped!
please Help and Thanks!
Which of the following shows the correct order of the levels of classification form Largest to smallest
Which type of mass movement is the most destructive
Answer:
Landslide
Explanation:
its most destructive because its various rocks falling and it goes blammow
Answer: the answer is C
Landslide
Explanation:
Many of the lunar craters are due to volcanic eruptions true or false
Answer:
false
Explanation:
Craters on the Moon are caused by asteroids and meteorites colliding with the lunar surface. The Moon's surface is covered with thousands of craters. ... It also has very little geologic activity (like volcanoes) or weathering (from wind or rain) so craters remain intact from billions of years.
The correct name for P5O2 is
Answer:
phosphorous(iii) oxide
Explanation:
Hope this helps! :)
Deoxyribonucleic acid is also referred to as
The answer is nucleic acid
Answer:
(DNA) is a molecule that encodes an organism's genetic blueprint
Explanation:
Deoxyribo Is the D
nucleic Is the N
acid Is the A
{DNA}
Hope that helps :)
What is the simplest whole-number ratio of atoms in a molecule or formula unit called?
O the molecular fomula
O the molar mass
O the percent composition
O the empirical formula
Answer:
the empirical formula
Explanation:
I remember learning this last year.
Answer:
the empirical formula
Explanation:
True Or False? A magnet slows down because it created an opposing electric force as it fell.
Answer:
faules
Explanation:
truck it
What is the speed of a car that has traveled 100 miles in 20 hours?
|
Answer:
5 mph
Explanation:
100 miles, 20 hours (divide by 2)
50 miles, 10 hours (divide by 2)
25 miles, 5 hours (divide by 2)
divide both sides by 5
5 miles, 1 hour
Answer:2
Explanation:
d = 24 g/ml
v = 1200 ml
m = ?
Answer:
28,800 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volume
From the question we have
mass = 24 × 1200
We have the final answer as
28,800 gHope this helps you
07-PS1-6 In a laboratory experiment that measures heat energy changes in 1 point
a chemical reaction, what is the most essential piece of equipment?*
Triple Beam Balance
Calculator
Hot Plate
Thermometer
Need answer now!
Which part of an atom is used to form bonds with other atoms?
Answer:
valence electrons
Explanation:
valence electrons