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Arturiano [62]
2 years ago
8

If Mary drove 525miles in 7hours at an average speed of 75 miles per hour how much faster would her average speed need to be to

make the trip in 5 hours ( a little speed demon!)
Chemistry
1 answer:
Makovka662 [10]2 years ago
6 0
<h3>Answer:</h3>

30 miles per hour faster

<h3>Explanation:</h3>

We are given;

  • Distance that Mary drove as 525 miles
  • Time she took as 7 hours
  • Average speed as 75 miles per hour

We are supposed to determine how fast the average speed would be if she made the trip in 5 hours.

  • We know that speed is given by dividing distance by time taken.
  • In this case distance remained constant

Therefore, we can determine the speed when she took 5 hours

  • Speed = Distance ÷ time

           = 525 miles ÷ 5 hours

           = 105 hours

Thus, the new speed would be 105 miles per hours

But, initial speed was 75 miles per hour

Therefore, she would travel 30 miles per hour faster to cover the journey in 5 hours.

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What happened to the volume of gas when the syringe was exposed to various temperature conditions? Using the concepts explored i
rewona [7]

Answer:

Thus, when the volume of the gas is exposed to a temperature above -273.15 K, the volume increases linearly with the temperature.

Explanation:

The expression for Charles's Law is shown below:

\frac {V_1}{T_1}=\frac {V_2}{T_2}

This states that the volume of the gas is directly proportional to the absolute temperature keeping the pressure conditions and the moles of the gas constant.

<u>Thus, when the volume of the gas is exposed to a temperature above -273.15 K, the volume increases linearly with the temperature. </u>

<u>For example , if the temperature of the gas is reduced to half, the volume also reduced to half. </u>

<u>At -273.15 K, according to Charles's law, it is possible to make the volume of an ideal gas = 0.</u>

5 0
2 years ago
A sample of ammonia gas at 75°c and 445 mm hg has a volume of 16.0 l. what volume will it occupy if the pressure rises to 1225 m
ioda
In this kind of exercises, you should  use the "ideal gas" rules: PV = nRT
P should be in Pascal: 
445mmHg = 59328Pa
1225mmHg = 163319Pa

V should be in cubic meter:
16L = 0.016 m3

R = \frac{PV}{nT} = constant
\frac{P1 V1}{n T} = \frac{P2 V2}{n T}
==> P1 * V1 = P2 * V2
V2 = \frac{P1 V1}{P2} = \frac{445 0.016}{1225}
V2 = 0.00581 m3 = 5.81 L


7 0
2 years ago
Calculate the number of grams of Mg needed for this reaction to release enough energy to increase the temperature of 78 mL of wa
Vaselesa [24]

Answer:

We need 1.1 grams of Mg

Explanation:

Step 1: Data given

Volume of water = 78 mL

Initial temperature = 29 °C

Final temperature = 78 °C

The standard heats of formation

−285.8 kJ/mol H2O(l)

−924.54 kJ/mol Mg(OH)2(s)

Step 2: The equation

The heat is produced by the following reaction:

Mg(s)+2H2O(l)→Mg(OH)2(s)+H2(g)

Step 3: Calculate the mass of Mg needed

Using the standard heats of formation:

−285.8 kJ/mol H2O(l)

−924.54 kJ/mol Mg(OH)2(s)

Mg(s) + 2 H2O(l) → Mg(OH)2(s) + H2(g)

−924.54 kJ − (2 * −285.8 kJ) = −352.94 kJ/mol Mg

(4.184 J/g·°C) * (78 g) * (78 - 29)°C = 15991.248 J required

(15991.248 J) / (352940 J/mol Mg) * (24.3 g Mg/mol) = 1.1 g Mg

We need 1.1 grams of Mg

7 0
2 years ago
What does it mean when a mineral has a definite chemical composition?
mote1985 [20]

Answer:

For a substance to classify as a mineral, it must lie within certain parameters. It should be an inorganic solid, that is naturally occurring in nature (not synthesized), with an ordered internal structure and a definite chemical composition.

By definite chemical composition, geologists mean that the mineral must be have chemical constituents that have an unvarying chemical composition, or a chemical composition that oscillates withing a very limited and specific range.

An example is the mineral, halite. It has a chemical composition of one sodium atom and one chloride atom, represented as NaCl and is unchanging in this composition throughout nature.

<h3>Hope this helps</h3>
4 0
2 years ago
A metal, M , of atomic mass 56 amu reacts with chlorine to form a salt that can be represented as MClx. A boiling point elevatio
Goryan [66]

Answer:

  MCl₂

Explanation:

The formula for boiling point elevation can be used to find x. The "complete dissociation" means there will be an ion of M and x ions of Cl in the solution. The number of moles of solute will be 30.2 grams divided by the molecular weight of MClx, where x is the variable we're trying to find.

  \Delta T=imK_b\qquad\text{where i=ions/mole, m=molality, $K_b\approx 0.512$}\\\\376.81-373.15=(x+1)\dfrac{\text{moles}}{\text{kg solvent}}(0.512)\\\\\dfrac{3.66}{0.512}=(x+1)\dfrac{\dfrac{30.2}{56+35.45x}}{0.1}=\dfrac{302(x+1)}{56+35.45x}\\\\\dfrac{3.66}{0.512\cdot 302}(56+35.45x)=x+1\\\\\dfrac{3.66\cdot 56}{0.512\cdot 302}-1=x\left(1-\dfrac{3.66\cdot 35.45}{0.512\cdot 302}\right)\\\\x=\dfrac{50.336}{24.877}\approx 2.023

Then the formula for the salt is MCl₂.

6 0
2 years ago
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