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3 years ago

How to measure with SI UNIT

1 answer:

8 0

The SI base units and their physical quantities are the metre for measurement of length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the candela for luminous intensity, and the mole for amount of substance.

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Please help asap How can the effects of technology be described? This is Science not Chemistry sry

Sindrei [870]

Answer:

Chemistry is used in forensic science to uncover information from physical evidence.

Hope this helps

7 0

4 years ago

Calculate the molality of a solution prepared by dissolving 175 g of KNO3 in 750 g of water. (round to nearest hundreth)

Wittaler [7]

We will get the molality from this formula:
Molality = no.of moles of solute / Kg of solvent

So first we need the no.of moles of KNO3 = the mass of KNO3 / molar mass of KNO3
no.of moles of KNO3 = 175 / 101.01 = 1.73 mol
By substitution in the molality formula:
∴ molality = 1.73 / (750/1000) = 2.3 Molal

6 0

3 years ago

Read 2 more answers

If the [H+] in a solution is 1 × 10–1 mol/L, what is the [OH–]? Show your work.

AVprozaik [17]

Hello!

The basic equations to solve this is
pH = -log[H+]
pOH = -log[OH-]
pH + pOH = 14
------------------------------------------------------------------------------------------------------
Find pH

pH = -log(1 * 10^-1)
pH = 1
------------------------------------------------------------------------------------------------------
Find pOH
1 + pOH = 14

pOH = 13
------------------------------------------------------------------------------------------------------
Find OH-
[OH-] = 10^(-pOH)
[OH-] = 1 * 10^-13mo/L

The answer is $[OH-] = 1 * 10^{-13} mol/L$

Hope this helps!

3 0

4 years ago

Electric power is measured in watts (1 W = 1 J/s). About 95% of the power output of an incandescent bulb is converted to heat an

nlexa [21]

Answer:

9.430 * 10¹⁷ protons per second whill shine on the book from a 62 W bulb

Explanation:

To answer this question, first let's calculate the energy of a single photon with a wavelength (λ) of 504 nm:

E = hc/λ

Where h is Planck's constant (6.626*10⁻³⁴ J·s) and c is the speed of light (3*10⁸ m/s).

E = 6.626*10⁻³⁴ J·s * 3*10⁸ m/s ÷ (504*10⁻⁹m) = 3.944 * 10⁻¹⁹ J.

So now we can make the equivalency for this problem, that

<u>1 proton = 3.944 * 10⁻¹⁹ J</u>

Now we convert watts from J/s to proton/s:

1 $\frac{J}{s}*\frac{1proton}{3.944*10^{-19}J}=2.535*10^{18} \frac{proton}{s}$ = 1 W

Solving the problem, a 62 W bulb converts 5% of its output into light, so:

62 * 5/100 = 3.1 W

3.1 watts are equal to [ 2.535*10¹⁸ proton/s * 3.1 ] = 7.858 * 10¹⁸ proton/s

Of those protons per second, 12% will shine on the chemistry textbook, thus:

7.858 * 10¹⁸ proton/s * 12/100 = 9.430 * 10¹⁷ protons/s

8 0

3 years ago

You are watching the Indy 500 car race on television with your brother. He says, "Did you know that these cars race at a speed o

madam [21]

Answer:

See explanation

Explanation:

All physical quantities are broadly classified into scalar quantities and vector quantities.

Scalar quantities have magnitude but do not have direction. Vector quantities have both magnitude and direction. Hence the main difference between a scalar quantity and a vector quantity is that a vector has direction while a scalar quantity does not.

Speed is a scalar quantity while velocity is a vector quantity. You have just specified a magnitude of 200 mph without mentioning its direction. This implies that you are referring to speed of the cars in the race and not velocity because velocity of the cars must indicate the direction!

8 0

3 years ago