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professor190
10 days ago
15

1. Bailey wants to find out which frozen solid melts the fastest: soda, gatorade, or orange juice. She pours each of the three l

iquids into the empty cubes of an ice tray, along with a forth liquid, plain water. She then places the ice tray in the freezer over night. The next day, she pulls the ice tray out and sets each cube on its
own plate. She then waits and watches for them to melt. When the last part of the frozen liquid melts, she records the time.

Independent Variable:
Dependent Variable:
Control(s):
Constants:

--

2. Jack wants to find out which laundry detergent cleans the best. So, he takes a cotton sheet and cuts it up into equal squares. He stains four squares with chocolate. He washes one of each of the squares in each of the 3 detergents, and the final square is washed in plain water. For each wash load, he used: the same amount of water, the same amount of detergent, and the same temperature of water.

Independent Variable:
Dependent Variable:
Control(s):
Constants:

---

Maverick wants to find out whether or not Miracle Grow really makes plants grow faster. He takes two identical pots, puts ½ cup of dirt into each one, puts 3 pea plant seeds into each one, and tops each off with ½ cup more dirt. He waters the plants the same amount at the same time each day. The only difference is that one plant is watered with regular water, while the other is watered with water that has Miracle Grow in it.

Independent Variable:
Dependent Variable:
Controls(s):
Constants:
Chemistry
2 answers:
Alekssandra [968]10 days ago
8 0

Answer:

Scientific investigations are conducted to evaluate hypotheses that involve three categories of variables: independent, dependent, and constant variables.

1. Independent variables: These can be controlled and adjusted during the experiment.

2. Dependent variables: These are assessed during the investigation.

3. Constant variables: These remain unchanged throughout the experiments but can influence the dependent variable.

4. Control: This is the sample that excludes the dependent variable.

Based on this, the variables identified in the examples are:

Case I

Independent variables-Time and night hours.

Dependent variables- state of the melting liquid  

Constant variable- freezer and ice tray

Control- plain water  

Case II

Independent variables- chocolate type, fabric type, fabric squares

Dependent variables- the type of detergent used

Constant variable- equal amounts of water, detergent, and temperature.

Control- square washed only with water.

Case III

Independent variables- Duration

Dependent variables- growth rate of the plant

Constant variable-  pots and the consistent water amount given

Control- pots without Miracle Grow watering

VMariaS [1K]10 days ago
4 0

First scenario:

IV: soda, gatorade, orange juice, and water

DV: state of the liquids listed above

Control: freezer and ice tray

Second scenario:

IV: laundry detergent, water

DV: cleanliness of the squares post-wash

Control: chocolate, cloth type, cloth squares

Third scenario:

IV: type of water used, pea plant

DV: growth of the pea plant

Control: pots and daily water amount for the plant

You might be interested in
The chemical formula for cesium oxide is Cs2O. What is the charge of cesium? +1 +2 –1 –2
lions [985]
The charge on cesium is +1
5 0
14 days ago
Read 2 more answers
A 85.2 g copper bar was heated to 221.32 degrees Celsius and placed in a coffee cup calorimeter containing 4250 mL of water at 2
eduard [944]

Answer:- 64015 J

Solution: The calorimeter contains 4250 mL of water, which is at a temperature of 22.55 degrees Celsius.

The water's density is 1 gram per mL.

Thus, the mass of water = 4250mL(\frac{1g}{1mL}) = 4250 grams.

After introducing the hot copper bar, the final temperature of the water reaches 26.15 degrees Celsius.

Thus, \Delta T for the water = 26.15 - 22.55 = 3.60 degrees Celsius.

The specific heat capacity of water is 4.184 \frac{J}{g.^0C}.

To determine the heat absorbed by the water, we can use the following formula:

q=mc\Delta T

where q represents heat energy, m refers to mass, and c indicates specific heat.

Now let's substitute the values into the equation to perform the calculations:

q=4250g*\frac{4.184J}{g.^0C}*3.60^0C

q = 64015 J

Therefore, the water absorbs 64015 J of heat.



5 0
7 days ago
If the kinetic energy of a particle is equal to twice its rest mass, what is the velocity of the particle? Determine if relativi
lorasvet [956]

Answer:

The particle's velocity is calculated to be 2 m/s,

Explanation:

Kinetic energy refers to the energy an object possesses due to its movement. The formula for kinetic energy is:

K.E=\frac{1}{2}mv^2

Where:

m = the mass of the object

v = the object's velocity

A particle with mass m has a kinetic energy that is double its mass.

K.E=2m

2m=\frac{1}{2}mv^2

v^2=\frac{4}{1}

v=2

Since the velocity is measured in m/s, we determine that the particle's speed is 2 m/s.

8 0
8 days ago
Ibuprofen, a headache remedy, contains 75.69% C, 8.80% H, and 15.51% O by mass and has a molar mass of 206 g/mol. Express your a
castortr0y [923]

Answer:

A) The molecular formula for ibuprofen isC_{13}H_{18}O_2

B) The molecular formula for Cadaverine is C_{5}H_{14}N_2

C) The molecular formula for Epinephrine is C_9H_{13}O_3N_1

Explanation:

Element percentage in a compound:

\frac{\text{Number of atoms of element}\times \text{Atomic mass of element}}{\text{molecular mass of element}}\times 100

A) The composition of ibuprofen, used for headaches, consists of 75.69% carbon, 8.80% hydrogen, and 15.51% oxygen by weight.

Ibuprofen has a molar mass of 206 g/mol.

The proposed molecular formula for ibuprofen is =C_xH_yO_z

Count of carbon atoms in one ibuprofen molecule;

75.69\%=\frac{x\times 12 g/mol}{206 g/mol}\times 100

x=\frac{75.69\times 206 g/mol}{100\times 12 g/mol}=12.99\approx 13

Count of hydrogen atoms in one ibuprofen molecule;

8.80\%=\frac{y\times 1 g/mol}{206 g/mol}\times 100

y=\frac{8.80\times 206 g/mol}{100\times 1 g/mol}=18.12\approx 18

Count of oxygen atoms in one ibuprofen molecule;

15.51\%=\frac{z\times 16 g/mol}{206 g/mol}\times 100

z=\frac{15.51\times 206 g/mol}{100\times 16 g/mol}=1.99\approx 2

Molecular formula for ibuprofen:

= C_xH_yO_z= C_{13}H_{18}O_2

B) Cadaverine consists of 58.55% carbon, 13.81% hydrogen, and 27.40% nitrogen by weight

Cadaverine has a molar mass of 102.2 g/mol.

The proposed molecular formula for Cadaverine is =C_xH_yN_z

Count of carbon atoms in one Cadaverine molecule;

58.55\%=\frac{x\times 12 g/mol}{102.2 g/mol}\times 100

x=\frac{58.55\times 102.2 g/mol}{100\times 12 g/mol}=4.98\approx 5

Count of hydrogen atoms in one Cadaverine molecule;

13.81\%=\frac{y\times 1 g/mol}{102.2 g/mol}\times 100

y=\frac{13.81\times 102.2 g/mol}{100\times 1 g/mol}=14.11\approx 14

Count of nitrogen atoms in one Cadaverine molecule;

27.40\%=\frac{z\times 14 g/mol}{102.2 g/mol}\times 100

z=\frac{27.40\times 102.2 g/mol}{100\times 14 g/mol}=2.00\approx 2

Molecular formula for Cadaverine:

= C_xH_yN_z= C_{5}H_{14}N_2

C) Epinephrine includes 59.0% carbon, 7.1% hydrogen, 26.2% oxygen, and 7.7% nitrogen by weight

Epinephrine has a molar mass of 180 g/mol.

The proposed molecular formula for Epinephrine is =C_xH_yO_zN_w

Count of carbon atoms in one Epinephrine molecule;

59.0\%=\frac{x\times 12 g/mol}{180 g/mol}\times 100

x=\frac{59.0\times 180 g/mol}{100\times 12 g/mol}=8.85\approx 9

Count of hydrogen atoms in one Epinephrine molecule;

7.1\%=\frac{y\times 1 g/mol}{180 g/mol}\times 100

y=\frac{7.1\times 180 g/mol}{100\times 1 g/mol}=12.78\approx 13

Count of oxygen atoms in one Epinephrine molecule;

26.2\%=\frac{z\times 16 g/mol}{180 g/mol}\times 100

z=\frac{26.2\times 180 g/mol}{100\times 16 g/mol}=2.94\approx 3

Count of nitrogen atoms in one Epinephrine molecule;

7.7\%=\frac{w\times 14 g/mol}{180 g/mol}\times 100

w=\frac{7.7\times 180 g/mol}{100\times 14 g/mol}=0.99\approx 1

Molecular formula for Epinephrine:

= C_xH_yO_zN_w= C_9H_{13}O_3N_1

7 0
11 days ago
The molar absorptivity of a compound at 500 nm wavelength is 252 M-1cm-1. Suppose one prepares a solution by dissolving 0.00140
lorasvet [956]

Answer:

The solution's absorbance measures 0.21168.

Explanation:

Provided that,

Wavelength = 500 nm

Molar absorptivity = 252 M⁻¹ cm⁻¹

Moles present = 0.00140

Total solution volume = 500.0 mL

Path length = 3.00 mm

We have to determine the molar concentration

Utilizing the formula for molar concentration

C=\dfrac{N}{V}

Where N = number of moles

V = volume

Input the values into the formula

C=\dfrac{0.00140}{0.5000}

C=0.0028\ M

Next, we will calculate the solution's absorbance

Using the absorbance formula

A=\epsilon C l

Substituting values into the equation

A=252\times0.0028\times0.300

A=0.21168

Therefore, the absorbance of the solution is 0.21168.

5 0
15 days ago
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