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Lubov Fominskaja [6]
3 years ago
15

Yasir wants to determine if there is a relationship between room color and sleep. Based on his research, Yasir makes an educated

guess that people fall asleep more quickly in a room painted blue than in a room painted yellow. He asks several people which color they like better -yellow or blue- and uses their responses to determine if his educated guess was correct. What is missing from Yasir’s scientific investigation?
A testable hypothesis that is based on research
An experiment that directly tests the hypothesis
Variables to be tested by an experiment Research on the topic to see what others have learned
Chemistry
2 answers:
kondaur [170]3 years ago
5 0

Answer:

Variables to be tested by an experiment Research on the topic to see what others have learned

Explanation:

Given that Yasir wants to determine if there is a relationship between room color and sleep. Based on his research, Yasir makes an educated guess that people fall asleep more quickly in a room painted blue than in a room painted yellow. He asks several people which color they like better -yellow or blue- and uses their responses to determine if his educated guess was correct.

The problem in his study is he really did not check the fact but depended on the reply of the people what the like

Sleep is different form liking a colour

Thus he should have recorded the paint colour and hours of sleep for a sample of reasonable size to test his hypothesis.

Variables to be tested by an experiment Research on the topic to see what others have learned is right answer

Fynjy0 [20]3 years ago
3 0

Yasir wanted to study the relationship between sleep and room color. So he has done all the background study required on the topic and arrived at a hypothesis that people fall asleep more rapidly in a room painted in blue color than in a room painted yellow. Yasir inquired several people which color they like better -yellow or blue- and used their feedback to decide whether his hypothesis was correct. There was no experiment conducted to observe the effect of a room color on sleep and the variables to be tested in the experiment were not properly identified.

Therefore, the correct answer would be,

An experiment that directly tests the hypothesis

Variables to be tested by an experiment

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15. Ammonium nitrate, NH4NO3, and aluminum powder react explosively producing nitrogen gas, water vapor and aluminum oxide. Writ
Lunna [17]

Answer:

2Al_(_S_) ~+~3NH_4NO_3_(_a_q_) ->3N_2_(_g_) ~+~6H_2O_(_g_) ~+~Al_2O_3_(_S_)

Entalpy=-2861.9~KJ

Explanation:

In this case, we have to start with the <u>reagents</u>:

Al~+~NH_4NO_3

The compounds given by the problem are:

-) <u>Nitrogen gas</u> =  N_2

-) <u>Water vapor</u>  =  H_2O

-) <u>Aluminum oxide</u> =  Al_2O_3

Now, we can put the products in the <u>reaction</u>:

Al_(_S_) ~+~NH_4NO_3_(_aq_) ->N_2_(_g_) ~+~H_2O_(_g_) ~+~Al_2O_3_(_S_)

When we <u>balance</u> the reaction we will obtain:

2Al_(_S_) ~+~3NH_4NO_3_(_a_q_) ->3N_2_(_g_) ~+~6H_2O_(_g_) ~+~Al_2O_3_(_S_)

Now, for the enthalpy change, we have to find the <u>standard enthalpy values</u>:

Al_(_S_)=0~KJ/mol

NH_4NO_3_(_a_q_)=-132.0~KJ/mol

N_2_(_g_)=0~KJ/mol

H_2O_(_g_)=~-~241.8~KJ/mol

Al_2O_3_(_S_)=~-~1675.7~KJ/mol

With this in mind, if we <u>multiply</u> the number of moles (in the balanced reaction) by the standard enthalpy value,  we can calculate the energy of the <u>reagents</u>:

(0*2)~+~(-132*3)=~-396~KJ

And the <u>products</u>:

(0*3)~+~(-241.8*6)~+~(-1675.7*1)=-3125.9~KJ

Finally, for the total enthalpy we have to <u>subtract</u> products by reagents :

(-3125.9~KJ)-(-396~KJ)=-2729.9~KJ

I hope it helps!

8 0
3 years ago
Calculate the total mass of the protons and electrons in 19 9F. Use 1.007825 amu as the mass of 11H (mass of a proton and an ele
SVETLANKA909090 [29]

Explanation:

Atomic mass means the sum of total number of protons and neutrons present in an atom.

When an atom is neutral then number of protons equal the number of electrons.

Mass of a proton equals to 1.007276 u, mass of neutron equals to 1.008664 u.

For example, in a ^{19}_{9}F atom there are total 9 protons and number of neutrons is 19 - 9 = 10.

Since, it is a neutral atom so number of electrons will also be 9.

So, total mass will be calculated as follows.

                  Total mass = 9 (mass of electron + mass of proton)

                                      = 9 (1.007825 u)

                                      = 9.07043 u

Therefore, we can conclude that total mass of protons and electrons in ^{19}_{9}F is  9.07043 u.

3 0
3 years ago
Which is an effect of the ozone depletion over Antarctica?
Crank

Answer:

Probably D (extensive DNA damage in the eggs...), maybe E (all of the above)

Explanation:

I'm looking for the answer myself becasue I'm not sure, but I'd probably go with D.

6 0
3 years ago
How does voltage work in a circuit?​
PIT_PIT [208]

Answer:

Voltage is the pressure from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop, enabling them to do work such as illuminating a light.

Explanation:

I hope this is right i found it off a website called fluke!

3 0
3 years ago
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Ratling [72]
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6 0
3 years ago
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