Explanation:
35- this is the answer in 2s.f
When rounding a number to two significant figures, we consider the first two most significant digits from the left. In this case, the number is 3456.5. 3456.5 rounded to two significant figures is 3500.
Rounding numbers is a common mathematical process used to simplify or approximate values to a desired level of precision. It involves adjusting a number to a specific decimal place or significant figure.
To round 3456.5 to two significant figures, we look at the first two digits: 34.
The next digit after the second significant digit is 5. Since 5 is greater than or equal to 5, we round up the last significant digit.
Therefore, rounding 3456.5 to two significant figures gives us:
3500
So, 3456.5 rounded to two significant figures is 3500.
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_____________ 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
To get a 4 suggest a way to improve the accuracy or precision of the finding
.
Chelsea went ice skating. The ice, her skates, the Zamboni, and the rink building were all examples of solids she encountered. She developed a model of the particles in the ice. Which of statements about the particles present in her model of solid are true?????? Choose the statements that apply.
A. they vibrate in place
B. they slide past each other
C. they are packed very closely together
D.they cause the solid to have a definite volume and definite shape
I think it is d c and a I may be wrong☺️
Answer:
Answers are C, D
Explanation:
Solid particles always stick together no matter what happens unless it is changing into a liquid. If you are talking about vibration for solid particles that only applies to thermal vibratio so not A. They do not slide past each other because they are packed very tightly together. They have a definite shape and volume because they stay together unless facing heat. Hopefully this helps you :)
pls mark brainlest ;)
The statements about the particles present in her model that are true;
C and D
They are packed very closely together ( C ) They cause the solid to have a definite volume and definite shape ( D )Particles of solids are closely packed and this feature distinguishes a solid from other forms of matter ( liquid and gas ). Solids have a definite volume and shape due to their closely packed particles.
Vibration in solids occur when solids are under thermal pressure and from her skating activity, there was no form of thermal pressure therefore solids vibrating in place would not be included in her model.
Hence we can conclude that The statements about the particles present in her model that are true; they are packed very closely together and They cause the solid to have a definite volume and definite shape
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In the reaction BaCl2 (aq) + Na2SO4 (aq) → BaSO4 (s) + 2NaCl (aq), what phases are the reactants in before the reaction?
Question 4 options:
A)
BaCl2 is a liquid, and Na2SO4 is a gas.
B)
BaCl2 is a solid, and Na2SO4 is in aqueous solution.
C)
Both reactants are gases.
D)
Both reactants are in aqueous solution.
Answer:
D. both are stated to be in aqueous solutions by the (aq)
Explanation:
Rank the nonmetals in each set from most reactive (1) to least reactive (3). bromine chlorine iodine
Answer:
1. Chlorine 2. Bromine 3. Iodine
Explanation:
Answer:
Bromine: 2 Chlorine: 1 Iodine: 3
Explanation:
All atoms that react
Answer: Electrons
Explanation:
What role does science play in changes?
Answer:
Science, as well as technological and metaphysical questions, should offer solutions to our everyday problems. The consistency of responses offered to society should be increased by research. Science, however, still needs to interact with society in conversation.
Explanation:
why do atoms combine
Explanation:
Atoms form chemical bonds with other atoms when there's an electrostatic attraction between them. This attraction results from the properties and characteristics of the atoms' outermost electrons, which are known as valence electrons.
The loops in Ptolemy’s model, and those shown on the video, are called motion. This phenomenon is caused by Earth’s orbit than those of other planets.
Answer:
The loops in Ptolemy’s ✔ geocentric model, and those shown on the video, are called
✔ retrograde motion. This phenomenon is caused by Earth’s
✔ faster orbit than those of other planets.
Explanation:
Answer:
✔ geocentric
✔ retrograde
✔ faster
Explanation:
What is the mass of an atom with 7 protons, and 7 neutrons?
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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Which of the following is a single replacement reaction?
( a. Ba(OH)2 + H2SO4 → BaSO4 + 2H2O
( b. 2Mg + O2 → 2MgO
(c. H2O+ CO2 → H2CO3
(d. Zn + H2SO4 → ZnSO4 + H2
Answer:
D.
Explanation:
A. is double replacement. Ex. AX + BY -> AY + BX
B. is synthesis Ex. A + B -> AB
C. is synthesis
D. is Single replacement -> A + BX -> Ax + B
- Study definitions and examples of these and that will help.
When zinc react with sulfuric acid, then zinc sulphate is formed. Zn + H₂SO₄ → ZnSO₄ + H₂ this reaction is replacement reaction.
What is replacement reaction ?One element in a molecule is replaced by another in a chemical reaction known as a single-displacement reaction, sometimes referred to as a single replacement reaction or exchange reaction.
One element in a compound is switched out for another in a single replacement reaction. In a double-replacement process, the anions or cations of two ionic compounds are switched. In a double-replacement reaction known as a precipitation, a solid precipitate is one of the products.
One ingredient replaces another comparable element in a compound in a single-replacement reaction.
Thus, option D is correct.
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What is the mass of 42.0 mL of a liquid with a density of 1.65 g/mL?
Answer:
The answer is
69.30 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume = 42 mL
density = 1.65 g/mL
The mass is
mass = 1.65 × 42
We have the final answer as
69.3 gHope this helps you
What is the term for a ratio of equivalent measurements that can be used to change a value from one until into another
Answer:conversion factor
Explanation:
- Write down Rutherford's atomic model with diagram .also write down defects of Rutherford's atomic model. - write down neil bohar atomic model
this is the answer
sorry if the answer is wrong
You are measuring the effects of salt on water's ability to freeze. To one of your water samples, you add sodium chloride (NaCl, or salt). In this solution, which part is the solvent?
Question 8 options:
Water
NaCl
Both
Neither
Answer:
water
water is the worlds best solvent cause it can melt many different things also it is called the "Universal Solvent"
Potassium, K, had 19 protons, 20 protons, 19 electrons. What is the charge of the atom’s nucleus.
HELP
Answer:
+ 19
Explanation:
The following data were obtained from the question:
Proton = 19
Neutron = 20
Electron = 19
Charge on nucleus =.?
From a background understanding of the structure of an atom, the nucleus of an atom contains protons and neutrons with the proton being positively charged and the neutron is neutral while the electrons being negatively charged revolve around the nucleus.
From the above question, we understood that the potassium atom has 19 protons which are all positively charged. This simply means that the nucleus has a charge of + 19 since the neutrons are neutral.
HELPPPP!
can we manufacture water? why or why not
Answer:
No because water needs to have no salt
Explanation:
Ex of physical Properties
Explain how NOTHING is ZERO, but ZERO is more than NOTHING?
Answer:
Nothing can be zero, but zero isn't nothing. If someone asks you if you have money and you say "I've got nothing!" when you actually don't have a cent, then you have zero money. However, zero is a number, so it itself is something, therefore more than nothing. So technically, you do have something.
When zero is on a number line, you could classify it as nothing, but it is the number between 1 and -1. Hypothetically speaking, if you took the zero away, wouldn't the number line be the same?
Zero isn't positive or negative. The number zero on a graph, or in a coordinate can tell you where something is. Zero can be a word to describe if something is existent, or non-existent.
Okay, my brain hurts.
All elements on the periodic table are________
Answer:
Explanation:
arranged in order of increasing.
What is density????????????????
Answer:
Density is the mass per unit volume
Explanation:
Density is defined as mass divided by volume: where "p" is the density, "m" is the mass, and "V" is the volume.
What should you always do at the end of a lab
Answer:clean up the area
Explanation:
Cats are aliens, sent to spy on us. Is this statement about cats a scientific theory? Explain your answer, including whether you can provide evidence to support the statement.
Answer:
No, it's not a scientific theory because it has no merit or evidence to support that claim.
Explanation:
25 PTS!
11. The metric prefix for 1/1000 is:
a) centi
b) milli
c) micro
d) kilo
how many bonds are broken in 2O2
Answer:
c5mvmifvidvj8dvj9r kf9,g
Question 8 Multiple Choice Worth 1 points)
(01 03 LC)
How is volume calculated given mass and density?
Sum of mass and density
O Mass divided by density
Mass multiplied by density
O Difference of mass and density
A what is the answer and
Anwser theses questions please (extra points!)
When salt is placed on ice the ice melts. explain why?
Explanation:
When salt is added to ice, salt first dissolves in the film of liquid water that is always present on the surface, thereby lowering the ice's freezing point
please mark as brainliest ,I really need it
which statement describes redis experiment which helped disprove spontaneous generation?
Answer:
it is A i just got it right
Explanation:
Discuss the sources and harmful effects of the following air pollutants.(i) Carbon monoxide (ii) Sulphur dioxide (iii) Oxides of nitrogen
Answer:
Oxides of Nitrogen (NOx)
NOx is a collective term used to refer to two species of oxides of nitrogen: nitric oxide (NO) and nitrogen dioxide (NO2).
Annual mean concentrations of NO2 in urban areas are generally in the range 10-45 ppb (20-90 µgm-3). Levels vary significantly throughout the day, with peaks generally occurring twice daily as a consequence of "rush hour" traffic. Maximum daily and one hourly means can be as high as 200 ppb (400 µgm-3) and 600 ppb (1200 µgm-3) respectively.
Globally, quantities of nitrogen oxides produced naturally (by bacterial and volcanic action and lightning) far outweigh anthropogenic (man-made) emissions. Anthropogenic emissions are mainly due to fossil fuel combustion from both stationary sources, i.e. power generation (21%), and mobile sources, i.e. transport (44%). Other atmospheric contributions come from non-combustion processes, for example nitric acid manufacture, welding processes and the use of explosives.
Sulphur Dioxide (SO2)
SO2 is a colourless gas. It reacts on the surface of a variety of airborne solid particles, is soluble in water and can be oxidised within airborne water droplets.
Annual mean concentrations in most major UK cities are now well below 35 ppb (100 µgm-3) with typical mean values in the range of 5-20 ppb (15-50 µgm-3). Hourly peak values can be 400-750 ppb (1000-2000 µgm-3) on infrequent occasions. Natural background levels are about 2 ppb (5 µgm-3).
The most important sources of SO2 are fossil fuel combustion, smelting, manufacture of sulphuric acid, conversion of wood pulp to paper, incineration of refuse and production of elemental sulphur. Coal burning is the single largest man-made source of SO2 accounting for about 50% of annual global emissions, with oil burning accounting for a further 25-30%.
Carbon Monoxide (CO)
Carbon Monoxide is a colourless, odourless, tasteless gas that is slightly lighter than air.
Natural background levels of CO fall in the range of 10-200 ppb. Levels in urban areas are highly variable, depending upon weather conditions and traffic density. 8-hour mean values are generally less than 10 ppm (12 mgm-3) but have been known to be as high as 500 ppm (600 mgm-3).
CO is an intermediate product through which all carbon species must pass when combusted in oxygen (O2). In the presence of an adequate supply of O2 most CO produced during combustion is immediately oxidised to carbon dioxide (CO2). However, this is not the case in spark ignition engines, especially under idling and deceleration conditions. Thus, the major source of atmospheric CO is the spark ignition combustion engine. Smaller contributions come from processes involving the combustion of organic matter, for example in power stations and waste incineration.
Ozone (O3)
O3 is the tri-atomic form of molecular oxygen. It is a strong oxidising agent, and hence highly reactive.
Background levels of O3 in Europe are usually less than 15 ppb but can be as 100 ppb during summer time photochemical smog episodes. In the UK ozone occurs in higher concentrations during summer than winter, in the south rather than the north and in rural rather than urban areas.
Most O3 in the troposphere (lower atmosphere) is formed indirectly by the action of sunlight on nitrogen dioxide - there are no direct emissions of O3 to the atmosphere. About 10 - 15% of tropospheric O3 is transported from the stratosphere where it is formed by the action of ultraviolet (UV) radiation on O2. In addition to O3, photochemical reactions involving sunlight produce a number of oxidants including peroxyacetyl nitrate (PAN), nitric acid and hydrogen peroxide, as well as secondary aldehydes, formic acid, fine particulates and an array of short lived radicals. As a result of the various reactions that take place, O3 tends to build up downwind of urban centres where most of NOx is emitted from vehicles.
Explanation: