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2 years ago

CORO Name three ways that scientists can ensure their results are reliable

Chemistry

1 answer:

Leya [2.2K]2 years ago

5 0

Answer:

Reliability. When a scientist repeats an experiment with a different group of people or a different batch of the same chemicals and gets very similar results then those results are said to be reliable. Reliability is measured by a percentage – if you get exactly the same results every time then they are 100% reliable.

Explanation:

Sorry, I only got one way.

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Imagine a 15kg block moving with a speed of 20m/s. Calculate the kinetic energy of this block.

SSSSS [86.1K]

The kinetic energy formula is;

$KE=\frac{m.v^2}{2}$

The variable $m$ represents the mass. Its unit is kilogram. We are informed that the mass of the object is $15kg$ . The variable $v$ represents the linear velocity. Its unit is meter per second. We are informed that the linear velocity of the object is $20m/s$ . Let's find the kinetic energy of the object by substituting these values in the formula.

$KE=\frac{15kg.(20m/s)^2}{2}$
$2.KE=15kg.400m^2/s^2$
$2.KE=(6000)kgm^2/s^2$
$KE=(3000)kgm^2/s^2=3000J$

5 0

1 year ago

Suppose it took 108 joules of energy to raise a bar of gold from 25 °C to 29.7°C. Given that the specific heat capacity of gold

Lady bird [3.3K]

Answer:

m = 180 g

Explanation:

Given data:

Energy absorbed = 108 J

Mas of gold = ?

Initial temperature = 25°C

Final temperature = 29.7 °C

Specific heat capacity of gold = 0.128 J/g.°C

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT =29.7 °C - 25°C

ΔT = 4.7 °C

108 J = m ×0.128 J/g.°C ×4.7 °C

108 J = m ×0.60 J/g

m = 108 J/0.60 J/g

m = 180 g

3 0

2 years ago

Which molecule has a dipole moment of 0 d?

fiasKO [112]

The answer is

a symmetrical molecule.

5 0

3 years ago

The vapor pressure of pure water at 25 °c is 23.8 torr. What is the vapor pressure (torr) of water above a solution prepared by

maxonik [38]

The vapour pressure of the solution is 23.4 torr.

Use Raoult’s Law to calculate the vapour pressure:

p₁ = χ₁p₁°

where

χ₁ = the mole fraction of the solvent

p₁ and p₁° are the vapour pressures of the solution and of the pure solvent

The formula for vapour pressure lowering Δp is

Δp = p₁° - p₁

Δp = p₁° - χ₁p₁° = p₁°(1 – χ₁) = χ₂p₁°

where χ₂ is the mole fraction of the solute.

Step 1. Calculate the mole fraction of glucose

n₂ = 18.0 g glu × (1 moL glu/180.0 g glu) = 0.1000 mol glu

n₁ = 95.0 g H_2O × (1 mol H_2O/18.02 g H_2O) = 5.272 mol H_2O

χ₂ = n₂/(n₁ + n₂) = 0.1000/(0.1000 + 5.272) = 0.1000/5.372 = 0.018 62

Step 2. Calculate the vapour pressure lowering

Δp = χ₂p₁° = 0.018 62 × 23.8 torr = 0.4430 torr

Step 3. Calculate the vapour pressure

p₁ = p₁° - Δp = 23.8 torr – 0.4430 torr = 23.4 torr

3 0

3 years ago

Alveoli are tiny sacs of air in the lungs. Their average diameter is 4.50 × 10−5 m. Calculate the uncertainty in the velocity of

Arisa [49]

Answer: The uncertainty in the velocity of oxygen molecule is $4.424\times 10^{-5}m/s$

Explanation:

The diameter of the molecule will be equal to the uncertainty in position.

The equation representing Heisenberg's uncertainty principle follows:

$\Delta x.\Delta p=\frac{h}{2\pi}$

where,

$\Delta x$ = uncertainty in position = d = $4.50\times 10^{-5}m$

$\Delta p$ = uncertainty in momentum = $m\Delta v$

m = mass of oxygen molecule = $5.30\times 10^{-26}kg$

h = Planck's constant = $6.627\times 10^{-34}kgm^2/s^2$

Putting values in above equation, we get:

$4.50\times 10^{-5}m\times 5.30\times 10^{-26}kg\times \Delta v=\frac{6.627\times 10^{-34}kgm^2/s}{2\times 3.14}\\\\\Delta v=\frac{6.627\times 10^{-34}kgm^2/s^2}{2\times 3.14\times 4.50\times 10^{-5}m\times 5.30\times 10^{-26}kg}=4.424\times 10^{-5}m/s$

Hence, the uncertainty in the velocity of oxygen molecule is $4.424\times 10^{-5}m/s$

8 0

3 years ago