Tom tells Greta that his father, an astronomer, is planning a scientific experiment to study another galaxy. Using a powerful telescope, Tom's father will record data of shifts in light patterns and track their different sources every 30 seconds. He will later study the data. Greta says that this is not an experiment. Which of these reasons supports Greta's statement?


It is not performed in a lab.


There are too many variables.


It does not have a control group.


It uses only theoretical predictions.

Answers

Answer 1

Answer:

it does not have a control group


Related Questions

The RDI for sodium for adults is 2300mg. What amount of table salt (in grams) contains this quantity of sodium? Express answer to two significant figures and include the appropriate units.

Answers

The rid. 384099 in the magic

The amount of table salt (in grams) contains this quantity of sodium is 5.844 g.

What is table salt?

Table salt is made up of sodium and chloride. The chemical formula of table salt is NaCl. This is a common salt used daily in the kitchen. This gives us a taste of food. And it is also necessary for the body.

The RDI for sodium for adults is given that is 2300 mg. The quantity of sodium is given = 2300 mg = 2.30 g (since the answer is asked in grams)

As we know, table salt is NaCl.

The molar mass of table salt (NaCl) is 58.44 g/mol

The molar mass of sodium (Na) is 23.00 g/mol

So, for 23.00 g sodium, we need 58.44 g NaCl.

And, for 2.30 g sodium we require (58.44 g x 2.3 g) / 23 g = 5.844 g = 6 g (to one significant figure).

Therefore, the amount of sodium is present in 5.844 grams of table salt.

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why is the Universal Law of Gravitation is a scientific Law and not a theory?

Answers

This is a law because it describes the force but makes not attempt to explain how the force works. A theory is an explanation of a natural phenomenon. Einstein's General Theory of Relativity explains how gravity works by describing gravity as the effect of curvature of four dimensional spacetime.

The scientific community dismissed John Needham’s attempt to prove spontaneous generation. What was the reason that they gave? *

A. By sealing off the flask he deprived the environment of air, a requirement of spontaneous generation


B. He used the wrong type of flask

C. He left the flasks open to the air for too long

D. He did not boil his broth long enough and the flasks were not cleaned prior to the experimenter.

Answers

Answer:

He did not boil his broth long enough and the flasks were not cleaned prior to the experimenter

Which of the following is not a derived unit?

A) g/ml

B) liter

C) kg

D) All of these are derived.

Answers

B. Liter is the answer

HELP!! please choose all the correct answers, picture attached

Answers

Answer:

Only C. is wrong else every option is correct.

Explanation:

Hope this helps you. If you want explanation then ask in comments. Good luck!

12) SEP Use Mathematics Complete the table by identifying the atomic number and
mass number for each atom and then using those data to determine the numbers
of protons, neutrons, and electrons.
Composition of Atoms
Atom
Atomic number
Mass number
Protons
Electrons
Neutrons
Na
2s
silver-108
47
T
gold-197
79
O
+ Back
Next →
INTL

Answers

The given elements are Na, Ag and Au.

1. Sodium(Na)

Mass number= 23 u

Atomic number=11

Number of protons= Number of electrons= Atomic number=11

Number of neutrons= Mass number- Number of protons=23-11=12

2. Silver (Ag)

Mass number= 108 u

Atomic number= 47

Number of protons= Number of electrons= Atomic number= 47

Number of neutrons= Mass number- Number of protons=108-47=61

3. Gold (Au)

Mass number= 197 u

Atomic number= 79

Number of protons= Number of electrons= Atomic number= 79

Number of neutrons= Mass number- Number of protons= 197-79=118

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Which best describes a meniscus?

Answers

A. the curved dip at the top of a liquid in a graduated cylinder.

Part A
Enter an equation for the precipitation reaction that occurs (if any) when solutions of ammonium chloride and calcium nitrate are mixed.
Express your answer as a chemical equation. Identify all of the phases in your answer. Enter noreaction if no precipitate is formed.
ΑΣΦ
?
2NH, Cl(aq) + Ca(NO3)2 (aq) +CaCl, (s) + 2N, O(g) + 4H, O(g)
DA chemical reaction does not occur for this question
Submit
Previous Answers Request Answer
X Incorrect; Try Again; One attempt remaining
Provide feedback

Answers

The equation of reacting ammonium chloride with calcium nitrate will be: [tex]Ca(NO3)_2(s) + 2NH_4CI(s) --- > 2N_2O(g) + CaCl_2(s) + 4H_2O(g)[/tex]

What are chemical reactions?

They are reactions involving chemical reactants.

Ammonium chloride, in solid form, will react with calcium nitrate, also in solid form to produce dinitrogen oxide gas, solid calcium chloride, and water vapor.

The equation of the reaction is represented as follows:

[tex]Ca(NO3)_2(s) + 2NH_4CI(s) --- > 2N_2O(g) + CaCl_2(s) + 4H_2O(g)[/tex]

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how toxic is uranium

Answers

Answer:

Inhaling large concentrations of uranium can cause lung cancer from the exposure to alpha particles. Uranium is also a toxic chemical, meaning that ingestion of uranium can cause kidney damage from its chemical properties much sooner than its radioactive properties would cause cancers of the bone or liver.

Explanation:

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Answers

Answer:

c. saturated

d. unsaturated

e. The solute isn't in the table G, so it is impossible to know

f. saturated

g. saturated

h. supersaturated

4. About 73 g

5. About 55 °C

6. About 58 °C

What is the relationship between number of electrons on the outer energy levels and
groups?

Answers

Answer:

Every element in a given group has the same number of valence electrons. For elements in the main groups (1-2, and 13-18), the number of valence electrons increases when moving from left to right along any period (row). The noble gases contain a full valence electron shell, which consists of eight electrons.

Explanation:

Hope this helps.

Answer:

Valence Electrons

Explanation:

Say you are looking at a neutrally charged carbon atom, it has 6 electrons. The first electron shell can hold 2 electrons. The next can hold 8, the next can hold 8 and the next can hold ten and so on... Well in the Carbon atom case, it has 6 electrons, 6-2 is 4, so the carbon atom at 4 valence electrons, which actually helps it in making organic molecules, which in turn also helps make something you might have heard of before, organisms, the best example being, humans

What is the mass number for an atom of xenon containing 54 protons and 75 neutrons?

Answers

Answer:

Answer should 133

Explanation:

all you have to do is add the protons and neutrons

The mass number for an atom of xenon containing 54 protons and 75 neutrons is 129 amu.

What is an Atomic mass of an atom?

The Atomic mass of any atom may be defined as the mass of an atom that is togetherly constituted by protons and neurons in the nucleus of an atom. It is approximately equivalent to the number of protons and neutrons in the atom (the mass number).

The mass number of Xenon is calculated by the following formula:

The Number of neutrons = Mass number - Atomic number.

where, number of neutrons = 75, and number of protons = 54.

75 = Mass number - 54 (number of protons = atomic number).

Mass number = 75 + 54 = 129 amu.

Therefore, the mass number for an atom of xenon containing 54 protons and 75 neutrons is 129 amu.

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is mercury homogeneous or heterogeneous?

Answers

Answer:

homogenous

Explanation:

its a pure element, so it is a pure substance

homogeneous
hope this helps!

How many protons and neutrons are in the nucleus of zinc-72

Answers

Answer:

30 protons

Explanation: Each zinc isotope contains 30 protons, 30 massive, positively charged nuclear particles

30 protons, 34 neutrons, and 30 electrons.

help please !!! THANK YOU !

Answers

Answer:The nucleus emits particles and/or energy.

Explanation:

A student wants to know why sandhill crane‘s fly south for the winter. The student uses a map of North America to make a model of the paths sandhill cranes take as they migrate. The student draws lines with arrows to show the routes sandhill cranes are known to take. Which two issues describe limitations of the students models?

Answers

Two limitations of the student's models are that the models do not explain why the phenomenon occurs and the models only record the phenomenon in a limited way

Understanding a specific phenomenon requires gathering and analyzing data thoroughly because the researcher needs to collect data that is directly related to the phenomenon and this data needs to be complete and accurate to have reliable conclusions.

In this situation, the student created some models of the routes of the sandhill crane's migration. This data has two main limitations:

It does not answer the question "why?": If the student wants to understand why these birds go to the South, the models are not very useful because they show "how" these birds migrate but not the reason for this migration.It records the migration only in a limited way: For the models to be complete the student needs to record the migration pattern for two years or more, as the pattern might change

Based on this, two limitations of the models are that they do not explain the phenomenon and the data is not complete.

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Look at the graph above showing the composition of air. Which component is the solvent?

Answers

The component that would be the solvent from the graph would be nitrogen.

From the graph, nitrogen takes up 78%, oxygen had 21%, while the remaining gases take the remaining 1%.

A solvent is a substance or the component of a solution that has the capacity to dissolve other substances

In a mixture consisting of 2 or more substances, the substance with the highest volume usually acts as the solvent.

In this case, nitrogen holds the highest volume of all the gases in the graph. Thus, it can be considered as the solvent while the remaining gases are the solutes.  

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ora
If a student is combining two
substances and sees bubbles and
is probably taking
fizzing, a
place.
A. chemical change
B. physical change

Answers

Answer:

A a chemical change

Explanation:

because a chemical change is when you mix tow substance together and they creat a new substance

why are noble gases considered the most stable elements

Answers

Answer:

they have the maximum number of valence electrons their outer shell can hold.

Explanation:

The accepted value of Ksp is 1.2×10−12 for Ag2CrO4. Calculate the percentage error if your experimentally determined value for Ksp was 1.5×10−10.

Answers

The percentage error in the experimental determination is 124%.

The experimentally determined value for Ksp = 1.5×10^−10

The accepted value of Ksp = 1.2 × 10^−12

The formula for percentage error is;

% error = absolute value of ( actual value - experimental value)/actual value × 100/1

% error = absolute value of (1.2 × 10^−12 - 1.5×10^−10)/ 1.2 × 10^−12 × 100/1

% error = 124%

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An unknown mass of each of the following substances, initially at 23.0 ∘C , absorbs 1940 J of heat. The final temperature is recorded as indicated. Find the mass of each substance. Pyrex glass (final temp:55.4 C)

Answers

The mass of the Pyrex glass that absorbs 1940J of energy is 79.52grams.

How to calculate mass?

The mass in a calorimetry procedure can be calculated using the following formula:

Q = mc∆T

Where;

Q = quantity of heat absorbed or releasedm = mass of substancec = specific heat capacity = 0.753Jg/°C∆T = change in temperature

According to this question, an unknown mass of each of the following substances, initially at 23.0∘C , absorbs 1940 J of heat. The final temperature is recorded as indicated. The mass can be calculated as follows:

1940 = m × 0.753 × (55.4°C - 23.0°C)

1940 = 24.39m

m = 79.52grams.

Therefore, 79.52grams is the mass of the pyrex glass.

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giuioiijihovicutxcvyg

Answers

Answer:

ajajbshdbrbxjdnd djxbxbx

Explanation:

hdjdndjsosnbdjdkx dkdmdbdjd

Yo can someone explain the heat of fusion and heat of vaporization thing to me?

Answers

Answer:

The heat of fusion is the amount of energy required to change a solid into a liquid at its melting point. When a liquid becomes a solid, freezing or solidification has occurred.  The heat of vaporization is the energy required to change a liquid into a gas at its boiling point.

Explanation:

Help again thank you lots of points for you keep helping I will give you a good review thanks!

Answers

Answer:

it would prob be planet y

The flame from the candle gives off back smoke. Is this sign of a physical change or a chemical change?

Answers

Answer:

Both physical and chemical changes

How many grams of liquid water can be heated by 8920 joules through a change in temperature of 30K?

Answers

Answer:

One of water's most significant properties is that it takes a lot of energy to heat it. Precisely, water has to absorb 4,184 Joules of heat (1 calorie) for the temperature of one kilogram of water to increase 1°C. For comparison sake, it only takes 385 Joules of heat to raise 1 kilogram of copper 1°C.

Explanation:

What mass of H2O is produced by the combustion of 1.00 mol of CH4?

CH4(g) + 202(g) → CO2(g) + 2H2O(e)

Answers

The mass of H2O is produced by the combustion of 1.00 mol of CH4 is 36.0 grams.

What do you mean by molar mass ?

The term molar mass is defined as the mass of 1 mole of that particular substance and number of grams per mole of a compound.

The balance chemical equation is as follows:

CH4(g) + 202(g) → CO2(g) + 2H2O(e)

The mass of H2O = 36.0 g

Calculating the mass of H2O produced

mass of H2O = 1.00 mol CH4 × (2 mol H2O / 1 mol CH4) × (18.015 g H2O / 1 mol H2O)

mass H2O = 36.0 grams

Thus, The mass of H2O is produced by the combustion of 1.00 mol of CH4 is 36.0 grams.

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Nadine was cooking a pot of potatoes on the stove. When the potatoes were don’t she needed to remove the potatoes for the water. Which separation technique would be most efficient and effective method for Nadine to use to achieve this

Answers

Answer:

boiling

Explanation:

what is the answer to (x+3)=4

Answers

Answer:

1

Explanation:

x + 3 =4

subtract 3 from 4

You are left with one.

Plug in the answer

1+3=4

how do i convert 9.5125 liters to gallons

Answers

Answer:

That would be 2.51293615

Explanation:

1 liter is equal to 0.264172 gallons.

What you would need to do is, multiply the total number of liters, which in this case is 9.5125, by 0.264172.

9.5125 x 0.264172 gets you 2.51293665.

I hope this helps! :)

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