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3 years ago

10

While washing his hands before the client consultation with Chloe, Jayden dripped some water onto the countertop. When he came b

ack later to wipe it up, it had evaporated. What happened to the drops of water?
The water underwent a chemical change.
The water underwent a physical change.
The water became an organic substance.
The water became a pure substance.

1 answer:

Alchen [17]3 years ago

6 0

Answer:

the water underwent a physical change. This is because the water simply changed states, and could become liquid again, but it will remain H20 throughout the time

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Help please thank you!

Mrrafil [7]

Answer:....................................

Explanation:

5 0

3 years ago

50.0 ml of 0.010m naoh was titrated with 0.50m hcl using a dropper pipet. if the average drop from the pipet has a volume of 0.0

creativ13 [48]

25 drops of acid is required to neutralize the 50.0 ml of 0.010m of NaOH in the experiment.

The equation of the reaction is;

NaOH(aq) + HCl(aq) ---------> NaCl(aq) + H2O(l)

We can use the titration formula;

CAVA/CBVB = NA/NB

CA= concentration of acid

VA = volume of acid

CB = concentration of base

VB = volume of base

NA = number of moles of acid

NB = number of moles of base

CB = 0.010 M

VB = 50.0 ml

CA = 0.50 M

VA = ?

NA = 1

NB = 1

Substituting values;

CAVANB = CBVBNA

VA = 0.010 × 50.0 × 1/ 0.50 × 1

VA = 1 ml

Since the total volume of acid used is 1 ml and each drop contains 0.040 ml

The number of drops required is 1ml/0.040 ml = 25 drops

Learn more: brainly.com/question/1527403

4 0

3 years ago

German physicist Werner Heisenberg related the uncertainty of an object\'s position (Δx) to the uncertainty in its velocity Δv.

Assoli18 [71]

Heisenberg's <em>Uncertainty Principle</em> gives a relationship between the standard deviation of an object's position and its momentum.

$\Delta p \cdot \Delta x = h / (4 \pi)$ where

$\Delta p$ the standard deviation of the object's <em>momentum,</em>
$\Delta x$ the standard deviation of the object's <em>position, </em>and
$h \approx 6.63 \times 10^{-34} \; \text{J} \cdot \text{s}$ the Planck's constant.

By definition, the momentum of the electron equals the product of its mass and velocity.

$p = m\cdot v$

Assuming that measurement of the mass of the electron $m$ is accurate. It is assumed to be a coefficient of constant value. The <em>standard deviation</em> in the electron's velocity is thus directly related to that of its mass. That is:

$\Delta p = m \cdot \Delta v$

$\Delta v = 0.01 \times 10^{6} \;\text{m}\cdot \text{s}^{-1}$ from the question;

$\Delta p = m\cdot v \\ \phantom{\Delta p} = 0.01 \times 10^{6} \; \text{m} \cdot \text{s}^{-1} \times 9.11 \times 10^{-31} \; \text{kg}\\\phantom{\Delta p} = 9.11 \times 10^{-27} \; \text{kg} \cdot \text{m}\cdot \text{s}^{-1}$

Convert the unit of the Planck's constant to base SI units (kg, m, s, etc.) if it was provided in derived units such as joules. Doing so would allow for a dimension analysis on the accuracy of the result.

$h = 6.63 \times 10^{-34} \; \text{J} \cdot \text{s}\\\phantom{h} = 6.63 \times 10^{-34} \; (\text{N}\cdot \text{m}) \cdot \text{s} \\\phantom{h} = 6.63 \times 10^{-34} \; ((\text{kg} \cdot \text{m}\cdot \text{s}^{-2}) \cdot \text{m}) \cdot \text{s}\\\phantom{h} = 6.63 \times 10^{-34} \; \text{kg} \cdot \text{m}^{2} \cdot \text{s}^{-1}$

Apply the <em>Uncertainty Principle</em>:

$\Delta x = h/ (4 \pi \cdot \Delta p)\\\phantom{\Delta x} = 6.63 \times 10^{-34} \; \text{kg} \cdot \text{m}^{2} \cdot \text{s}^{-1} / (4 \pi \cdot 9.11\times 10^{-27} \; \text{kg} \cdot \text{m}\cdot \text{s}^{-1})\\\phantom{\Delta x} = 5.79 \times 10^{-9} \; \text{m}$ .

Dimensional analysis:

$\Delta x$ resembles the <em>standard deviation</em> of a position measurement. It is expected to have a unit of meter, which is the same as that of position.

3 0

3 years ago

Calculate the pH of milk with a hydrogen ionconcentration of 4.25 x 10^-7 mol dm-3. Show all steps ofyour calculations and inclu

yulyashka [42]

Answer:

6.37.

Explanation:

What is given?

[H (+)] = 4.25 x 10⁻⁷ mol/dm³

Step-by-step solution:

First, let's see the formula to calculate the pH based on the hydrogen ion concentration (H (+)):

$pH=-log\lbrack H^+].$

*Logarithm must be in base 10!

Our given concentration of hydrogen ion is 4.25 x 10⁻⁷ mol/dm³. Remember that the units of concentration must be in M (mol/L) but in this case, 1 dm³ equals 1 L, so based on this, we have that:

$4.25\cdot10^{-7}\frac{mol}{dm^3}=4.25\cdot10^{-7}\frac{mol}{L}.$

So, we can replace this value in the formula of pH:

$pH=-log\lbrack4.25\cdot10^{-7}]\approx6.37.$

The pH of milk would be 6.37 which means that is slightly acid (weak acid).

5 0

1 year ago

How long must a constant current of 50.0 A be passed through an electrolytic cell containing aqueous Cu2+ ions to produce 5.00 m

frozen [14]

Answer:

D) 5.36 hours

Explanation:

According to mole concept:

1 mole of an atom contains $6.022\times 10^{23}$ number of particles.

We know that:

Charge on 1 electron = $1.6\times 10^{-19}C$

Also, copper will produce 2 electrons. So, out of 5 moles of copper, 10 moles of electrons will be produced.

So,

Charge on 10 mole of electrons = $10\times 1.6\times 10^{-19}\times 6.022\times 10^{23}=9.6352\times 10^5C$

To calculate the time required, we use the equation:

$I=\frac{q}{t}$

where,

I = current passed = 50.0 A

q = total charge = $9.6352\times 10^5C$

t = time required = ?

Putting values in above equation, we get:

$50.0A=\frac{9.6352\times 10^5C}{t}\\\\t=\frac{9.6352\times 10^5C}{50.0A}=19270.4s$

Converting this into hours, we use the conversion factor:

1 hr = 3600 seconds

So, $19270.4s\times \frac{1hr}{3600s}=5.36hr$

Hence, the amount of time needed is 5.36 hrs.

8 0

3 years ago