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3 years ago

6

Why might it be important to test one variable at a time when doing an experiment?

1 answer:

Vanyuwa [196]3 years ago

4 0

Answer:

If you change everything at once, you may not know what caused the end result.

Explanation:

If you have Variable A (Salt), Variable B (Potassium), and the Control of Water, you might mix everything together, so you mix salt, potassium and water together. It is known that Potassium reacts very aggressively in water, but since you mixed everything together, you might think that salt+potassium+water goes boom, while it is actually potassium+water=boom.

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Convert 15.78 g of H2O2 to mols. <br> Convert 15.3 mols Au to g

iren2701 [21]

Answer:

.46 moles H2O2

3,014 grams Au

Explanation:

H2O2:

15.78g (1 mol/34g) = .46 moles H2O2

Au:

15.3mol (197g/mol) = 3,014 grams Au

8 0

3 years ago

4.91 M NaOH solution (density=1.04g/ mL)

hodyreva [135]

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3 years ago

Air bags are activated when a severe impact causes a steel ball to compress a spring and electrically ignite a detonator cap. Th

Vlada [557]

Answer:

the mass required to inflate a 72 L bag is 191.491 g

Explanation:

reaction:

2 NaN3 ↔ 2 Na + 3 N2

conditions:

V = 72.0 L
STP: P = 1 atm ∧ T = 298 K

gas law:

PV = RTn
R = 0.082 atm * L / K * mol

⇒ n = PV / RT

⇒ n = ((1 atm) * ( 72.0 L)) / (0.082 atm*L / K*mol) * (298 K)

⇒ n = 2.946 mol

⇒ m = n * Mw = ( 2.946 mol ) * ( 64.99 g/mol)

⇒ m = 191.491 g

7 0

3 years ago

How salt solution can be determined by using hydrometer

goldenfox [79]

Answer:

Salt solution may be calculated by measuring the specific gravity of a sample of water using a hydrometer.

<em>Hope</em><em> this</em><em> answer</em><em> correct</em><em> </em><em>(</em><em>^</em><em>^</em><em>)</em><em>.</em><em>.</em><em>.</em><em>.</em>

3 0

3 years ago

A chunk of tin weighing 18.5 grams and originally at 97.38 °C is dropped into an insulated cup containing 75.7 grams of water at

weqwewe [10]

Answer:

22.44°C will be the final temperature of the water.

Explanation:

Heat lost by tin will be equal to heat gained by the water

$-Q_1=Q_2$

Mass of tin = $m_1=18.5 g$

Specific heat capacity of tin = $c_1=0.21 J/g^oC$

Initial temperature of the tin = $T_1=97.38^oC$

Final temperature = $T_2$ =T

$Q_1=m_1c_1\times (T-T_1)$

Mass of water= $m_2=75.7 g$

Specific heat capacity of water= $c_2=4.184 J/g^oC$

Initial temperature of the water = $T_3=21.52^oC$

Final temperature of water = $T_2$ =T

$Q_2=m_2c_2\times (T-T_3)$

$-Q_1=Q_2$

$-(m_1c_1\times (T-T_1))=m_2c_2\times (T-T_3)$

On substituting all values:

$-(18.5 g\times 0.21 J/g^oC\times (T-97.38^oC))=75.7 g\times 4.184 J/g^oC\times (T-21.52 ^oC)$

we get, T = 22.44°C

22.44°C will be the final temperature of the water.

5 0

3 years ago