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xxTIMURxx [149]
2 years ago
9

I NEED HELP ON THIS WORTH 20 POINTS :)

Chemistry
2 answers:
Kamila [148]2 years ago
6 0

Answer:

option c is correct

Explanation:

please mark me as brainlist

Arturiano [62]2 years ago
4 0

Answer: C. mollusca and arthropoda

                                                                           

Explanation:

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Emily wanted to see what battery lasted the longest. She put each battery into a clock and recorded the time that the clock stop
Andru [333]

Answer:

independent variable -- different batteries

dependent variable -- the time that clock stop

Explanation:

In an experiment or a research study, there are two type of variables that can affect the result of the experiment or the conclusion. They are independent variable and the dependent variable.

An independent variable may be defined as that variable in an experiment which can be changed or can be controlled in the scientific experiment in order to test the effect on the dependent variable. It cannot be changed by other variables.

On the other hand, dependent variable are those are those which can be altered or change that can affect the experiment.

In the context, Emily uses  the different types of the batteries as an independent variable and the time where the clock stopped in the dependent variable in her research.

6 0
3 years ago
Substance A and B are the same mass and at the same initial temperature. When the same amount of heat is added to each, the fina
Bingel [31]
That both of them are warm....at a certain temputurature causing one to fell,cozy
7 0
3 years ago
(Physical Science)
Vera_Pavlovna [14]
Alkaline earth metals
4 0
2 years ago
A gas occupies 200ml at a temperature of 26 degrees Celsius and 76mmHg pressure. Find the volume at -3degree Celsius with the pr
sergey [27]

Answer:

184.62 ml

Explanation:

Let p_1, v_1, and T_1 be the initial and p_2, v_2, and T_2 be the final pressure, volume, and temperature of the gas respectively.

Given that the pressure remains constant, so

p_1=p_2 ...(i)

v_1 = 200 ml

T_1= 26 ^{\circ}C = 273+26 =299 K

T_2= 3 ^{\circ}C = 273+3 =276 K

From the ideal gas equation, pv=mRT

Where p is the pressure, v is the volume, T is the temperature in Kelvin, m is the mass of air in kg, R is the specific gas constant.

For the initial condition,

p_1v_1=mRT_1 \\\\mR= \frac{p_1v_1}{T_1}\cdots(ii)

For the final condition,

p_2v_2=mRT_2 \\\\mR= \frac{p_2v_2}{T_2}\cdots(iii)

Equating equation (i), and (ii)

\frac{p_1v_1}{T_1}=\frac{p_2v_2}{T_2}

\frac{v_1}{T_1}=\frac{v_2}{T_2}  [from equation (i)]

v_2=\frac{T_2}{T_1} \times v_1

Putting all the given values, we have

v_2=\frac{276}{299} \times 200 = 184.62 \; ml

Hence, the volume of the gas at 3 degrees Celsius is 184.62 ml.

7 0
2 years ago
A solution is prepared from 4.5701 g of magnesium chloride and 43.238 g of water. The vapor pressure of water above this solutio
balandron [24]

Answer:

i = 2.483

Explanation:

The vapour pressure lowering formula is:

Pₐ = Xₐ×P⁰ₐ <em>(1)</em>

For electrolytes:

Pₐ = nH₂O / (nH₂O + inMgCl₂)×P⁰ₐ

Where:

Pₐ is vapor pressure of solution (<em>0.3624atm</em>), nH₂O are moles of water, nMgCl₂ are moles of MgCl₂, i is Van't Hoff Factor, Xₐ is mole fraction of solvent and P⁰ₐ is pressure of pure solvent (<em>0.3804atm</em>)

4.5701g of MgCl₂ are:

4.5701g ₓ (1mol / 95.211g) = 0.048000 moles

43.238g of water are:

43.238g ₓ (1mol / 18.015g) = 2.400 moles

Replacing in (1):

0.3624atm = 2,4mol / (2.4mol + i*0.048mol)×0.3804atm

0.3624atm / 0.3804atm = 2,4mol / (2.4mol + i*0.048mol)

2.4mol + i*0.048mol = 2.4mol / 0.9527

2.4mol + i*0.048mol = 2.5192mol

i*0.048mol = 2.5192mol - 2.4mol

i = 0.1192mol / 0.048mol

<em>i = 2.483</em>

<em />

I hope it helps!

4 0
3 years ago
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