Answer:
ancient Egyptian event lighthouses including the huge lighthouse of Alexandria
Explanation:
-250 BCE
Identity which statement is true:
A. Isotopes of the same element have the same atomic number and mass number, but a different
number of neutrons.
B. Isotopes of the same element have the same mass number and different atomic numbers.
C. Isotopes of the same element have the same atomic number and different mass numbers.
D. Isotopes of the same element have the same number of neutrons and a different number of protons.
Isotopes of the same element have the same atomic number and different mass numbers. Hence, option C is correct.
What are Isotopes?Isotopes are defined as chemical species which have the same number of protons but differ in the number of neutrons.
It can also be said that they are the chemical species of the same element which have the same atomic number but have different mass numbers.
For Example, C12 and C14 are the isotopes of carbon elements, which have the same atomic number but a different mass numbers.
Hence, option C is correct.
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If you find the mass of a sample to be 42.1 g and the actual mass is 42.0 g. What wold be the percent error
Answer:
0.24%
Explanation:
The following data were obtained from the question:
Measured value = 42.1 g
Actual value = 42 g
Percentage error =?
Percentage error can be obtained by using the following formula:
Percentage error = |Measured value – Actual value | / Actual value × 100
With the above formula, we can obtain the percentage error as follow:
Measured value = 42.1 g
Actual value = 42 g
Percentage error =?
Percentage error = |42.1 – 42| / 42 × 100
Percentage error = 0.1/42 × 100
Percentage error = 10/42
Percentage error = 0.24%
Therefore, the percentage error is 0.24%
What is the frequency of individuals with doctorates who work in the field of physical science? 0-1,000 1,000-2,000 2,000-3,000 3,000-4,000
Answer: The answer is option B
1,000-2,000
Explanation:
What is 6.9 x 10^-3 in standard form?
Answer:
0.0069
Explanation:
When converting between scientific notation try to remember that moving the decimal place to the left is positve and to the right is negative
Since you are changing from scientific to standard you will need to move to the left from the decimal point, making your answer 0.0069
Which statement accurately describes humidity?
O Humidity is a measure of dew in the air.
O Colder air promotes more evaporation.
O Cold air holds more moisture than warm air.
O Humidity refers to the amount of water vapor in the air.
Humidity refers to the amount of water vapor in the air accurately describes it.
What is Water vapor?This can be defined as the gaseous phase of water as a result of heating in the atmosphere.
The amount of the water vapor in air is what is referred to as humidity which makes option D the most appropriate choice.
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True or False: PERIODS on the periodic table run up and down.
Answer:
True
Explanation:
I guessed XD But I also used Google and that's what I got
At 20 degrees Celsius the density of mercury is 13.6 g/cm cubed. What is the mass of 50.0 ml of mercury at 20 degrees Celsius?
The value of mass is 680 g.
Density:-
It is defined as mass per unit volume.
Given:-
[tex]Density=13.6\ g/cm^{3} \\Volume=50\ mL[/tex]
Calculate mass as follows:-
[tex]Density=Mass/Volume\\13.6\ g/cm^{3} = Mass/50.0\ mL\\Mass=13.6\ g/cm^{3} \times50.0\ mL[/tex]
Relationship used:-
[tex]1\ cm^{3} =1\ mL[/tex]
[tex]Mass=680\ g[/tex]
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What is the elixir of life
Answer:
The elixir of life, also known as elixir of immortality and sometimes equated with the name philosopher's stone, is a potion that supposedly grants the drinker eternal life and/or eternal youth. This elixir was also said to cure all diseases.
what claim is being made?
Answer:
D
Explanation:
because it's saying the diet soda has more calories then regular soda it's like someone claimed you of doing something you didn't do and they don't know that
What is the maximum number of covalent bonds that an oxygen atom with atomic number 8 can make with hydrogen?
Answer:
2
Explanation:
Oxygen has 6 electrons in its valence shell. Since an atom can have a maximum of 8 electrons in the valence shell, oxygen has 2 empty spots in its valence. This means that oxygen can make 2 single covalent bonds.
The maximum number of covalent bonds that an oxygen atom with atomic number 8 can make with hydrogen is: 2.
Valency can be defined as a measure of the combining power of a chemical element with other atoms to form a molecule or chemical compound. Typically, valency is measured by the amount of hydrogen atoms that a chemical element can combine with or displace to form a molecule or chemical compound.
Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others.
From the periodic table, we know that an oxygen atom has an atomic number of eight (8). Thus, oxygen has six (6) electrons in its valence shell and two (2) empty shells to form a covalent bond with hydrogen.
Generally, the maximum number of electrons an atom can hold in its valence shell is eight (8) and since oxygen has has six (6) electrons in its valence shell; it ultimately implies that the maximum number of covalent bonds that an oxygen atom with atomic number of eight (8) can make with hydrogen is two (2) covalent bonds.
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Please help me fast, i don't understand it.
Oleophilic materials would not be used for ?
Answer:
An oleophilic material is an entity which exhibits a higher affinity for oil than other solvents. The non-polar nature and ability to form cluster-like structures called micelles are the characteristic properties of oleophilic materials.
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Fill in the blanks with the correct word. During diffusion, molecules move from areas of concentration to areas of Diffusion does not require to move molecules. concentration. Previous Activity
TRY A LITTLE -_-
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Answer:
1) higher
2) lower
1) energy
Explanation:
hope this helps you.
I would really like a brainliest :D
thank you and have a nice day.
Answer:
1) higher
2) lower
1) energy
Explanation:
how were you able to identify the periods?
Answer:
This question is incomplete
Explanation:
This question is incomplete. However, the period of the periodic table are the horizontal (left to right) rows in the periodic table. Elements in the same period have the same number of electron shells. There are seven periods in the periodic table.
The periodic table of elements is the table that contains all chemical elements arranged according to there atomic number. Atomic number is the number of protons present in the nucleus of an atom.
significant figure of 87 000 ms
Answer:
2 significant figures.
Explanation:
Significant Figures Rules:
1. Anything that isn't a zero is a sig fig
2. If a decimal point comes after the ones digit, everything before the decimal is counted as sig fig (i.e 2000. would be 4 sig figs).
3. If we are dealing with small decimals, the zero before and after the decimal (i.e 0.002) is a placeholder and is not counted as sig figs.
4. Any zeros between 2 significant digits is considered in sig figs (i.e 2002 would be 4 sig figs)
Since we are dealing with 87000, we see that we have no decimal point. That means our only sig figs are 8 and 7, which equals 2 sig figs.
If the size, mass, and arrangement of atoms affect the density of a substance. How might these factors work together to cause a substance to have a low density?
Answer: The size, mass, and arrangement of atoms affect the density of a substance. How might these factors work together to cause a substance to have a high density? A substance with smaller more massive atoms that are close together is going to have a higher density.
Explanation:
1)Describe pure sand and pure salt. Use a hand lens if available to get more detail. Type a description. a)sand b)salt 2)Investigate the dissolving properties of pure sand and pure salt. Which one will be caught in the filter paper if each substance was mixed with water and then filtered? Filter both separately if you are not sure. Devise a plan to get pure sand and pure salt in different piles from a 1 gram sample of the mixture. Include in your plan:
Answer:
See explanation
Explanation:
A salt is made up of homogeneous particles while sand is made up of heterogeneous particles. Salt is a crystalline substance while sand is a coarse substance.
If salt and sand are mixed with water, salt forms a solution with water, hence, salt cannot be caught on filter paper. However, sand does not form any chemical specie with water hence it is caught on the filter paper as a solid.
Н - О - Н
I have to find the Molecular formula
Question 1
10 pts
A student fills a graduated cylinder with water to a volume of 22.4mL. After adding a
metal sample, the volume of the water rises to 26.2 mL. What is the volume of the
metal sample?
3.8 ml
0 22.4 mL
0 26.2 mL
O 48.6 mL
Answer:
3.8
Explanation:
2. Name a tool that is good for measuring the volume of a liquid accurately.
3. Name a tool that is good for estimating the volume of a liquid.
4. What tool would you use to measure the dimensions of a bedroom?
Answer:
[See Below]
Explanation:
✦ A beaker of liquid would measure the volume of a liquid.
✦ A graduated cylinder is good for estimating the volume of a liquid.
✦ You'd most likely use a tape measure to measure the wall length and width.
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How many grams are there in 1.45 kg?
Answer:
1.45 kg
Explanation:
common sense ok
Answer:
1450 grams are in 1.45 kilograms
Which is the best practice recommended in the safety video to mix and acid or a base with a solvent?
Answer:
Never pour water into acid but acid into water
Explanation:
If water is poured into extremely concentrated acid/bases, the rate of volatility and exothermic reaction is too rapid and might cause a chemical eruption, leading to acid burns.
Safety precautions hence dictate the reverse is practiced.
I believe this is a clear answer.
3 facts about the core
Answer:
The inner core is a hot, dense ball of (mostly) iron. It has a radius of about 1,220 kilometers (758 miles). Temperature in the inner core is about 5,200° Celsius (9,392° Fahrenheit). The pressure is nearly 3.6 million atmosphere (atm).
Explanation:
ln what ways are solid- solid mixture categorized
Answer:
homogeneous mixture
what is the mass of 975 mL of mercury? Its density is 13.5 g/mL
Answer:
72.22 g
Explanation:
975 mL Mercury× 13.5 g/mL = 72.22 g
Find the density in g/cm^3 of chalk, if 6.356 g occupy 2.56 cm^3
Answer:
Density = 2.48 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
From the question
mass = 6.356 g
volume = 2.56 cm³
Substitute the values into the above formula and solve.
That's
[tex]Density = \frac{6.356}{2.56} \\ = 2.4828125[/tex]
We have the final answer as
Density = 2.48 g/cm³
Hope this helps you
what are the trends of group 1 metals on the periodic table as the metals go down?
Answer:
The reactivity of group 1 elements increases as you go down the group because: the atoms become larger. the outer electron becomes further from the nucleus. the force of attraction between the nucleus and the outer electron decreases.
Explanation:
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In recent research, strontium ions have been used for bone regeneration within humans as a calcium replacement. Based on your knowledge of periodic information, explain why is strontium a good substitute for calcium instead of other elements on the periodic table. [Hint: think about the way elements are organized based on their common characteristics] *
Answer:
Strontium, as opposed to other elements on the periodic table (with the exception of others in the same group/column i.e., the vertical direction), is a good substitute for Calcium because they are in the same group.
Explanation:
This is because elements of the same group behave similarly and have similar properties. This is due to the fact that elements of the same group (in the vertical direction) have the same number of valence electrons.
Which of the following properly describes the movement of atoms as they represent the states of matter? Atoms making liquids have less attraction than solids, but more than gases Atoms making liquids have less attraction than solids, but more than gases The atoms making liquids are closer together than atoms making solids. The atoms making liquids are closer together than atoms making solids. The atoms that make solids do not move at all which is why they keep their shape. The atoms that make solids do not move at all which is why they keep their shape. Atoms making gases have the least amount of kinetic energy while solids have the most.
Answer:
Atoms making liquids have less attraction than solids, but more than gases
Explanation:
The attraction between atoms in different molecules in a solid is very strong due to strong intermolecular forces present in a solid. However, such intermolecular forces are weaker in liquids than in solids.
This implies that the solid has higher intermolecular forces of attraction compared to gases and liquids. Based on the negligible degree of intermolecular forces between them, a gas has the weakest intermolecular forces hence the atom has very minimal interaction between them.