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3 years ago

Which of the following is NOT true about energy?*

Chemistry

1 answer:

Montano1993 [528]3 years ago

7 0

Answer:

the last one

Explanation:

although energy can be transferred it does not change after a transfer

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Radio waves travel at the speed of light which is 3.00 x 10^8. How many minutes does it take for a radio message to reach saturn

ryzh [129]

Answer:

43.89 min

Explanation:

Given that:-

The speed of light = $3.00\times 10^8\ m/s$

The distance = $7.9\times 10^8\ km$

The conversion of distance in km to distance into m is shown below as:-

1 km = 1000 m

So,

Distance = $7.9\times 10^8\times 1000\ m=7.9\times 10^{11}\ m$

The relation between speed distance and time is shown below as:-

$Speed=\frac{Distance}{Time}$

Thus,

$3.00\times 10^8=\frac{7.9\times 10^{11}}{Time}$

$300000000\times time=10^{11}\times \:7.9\ s$

Time = 2633.33 seconds

Also, 1 s = 1/60 min

So,

Time= $\frac{2633.33}{60}\ min=43.89\ min$

3 0

3 years ago

A theory is:

SpyIntel [72]

A theory is a proposed explanation for an observation

3 0

2 years ago

How many moles of neon atoms are there in a neon sign that has 2.4 * 20^ 24 atoms of neon? *

Whitepunk [10]

Answer:

4 moles of neon

Explanation:

Given data:

Number of moles of neon = ?

Number of atoms of neon = 2.4×10²⁴ atoms

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For given neon atoms:

1 mol = 6.022 × 10²³ atoms

2.4×10²⁴ atoms × 1 mol / 6.022 × 10²³ atoms

0.4×10¹ mol = 4 mol

3 0

3 years ago

A 25.0-mL sample of 0.150 M hydrocyanic acid is titrated with a 0.150 M NaOH solution. The Ka of hydrocyanic acid is 4.9 × 10-10

lara [203]

Answer:

The pOH = 1.83

Explanation:

Step 1: Data given

volume of the sample = 25.0 mL

Molarity of hydrocyanic acid = 0.150 M

Molarity of NaOH = 0.150 M

Ka of hydrocyanic acid = 4.9 * 10^-10

Step 2: The balanced equation

HCN + NaOH → NaCN + H2O

Step 3: Calculate the number of moles hydrocyanic acid (HCN)

Moles HCN = molarity * volume

Moles HCN = 0.150 M * 0.0250 L

Moles HCN = 0.00375 moles

Step 3: Calculate moles NaOH

Moles NaOH = 0.150 M * 0.0305 L

Moles NaOH = 0.004575 moles

Step 4: Calculate the limiting reactant

0.00375 moles HCN will react with 0.004575 moles NaOH

HCN is the limiting reactant. It will completely be reacted. There will react 0.00375 moles NaOH. There will remain 0.004575 - 0.00375 = 0.000825 moles NaOH

Step 5: Calculate molarity of NaOH

Molarity NaOH = moles NaOH / volume

Molarity NaOH = 0.000825 moles / 0.0555 L

Molarity NaOH = 0.0149 M

Step 6: Calculate pOH

pOH = -log [OH-]

pOH = -log (0.0149)

pOH = 1.83

The pOH = 1.83

6 0

3 years ago

to checkt the accuracy of a new method, a standard copper alloy containing 23.24%Cu was analyzed and calculated to contain 23.17

tekilochka [14]

Answer:

23.24%_23.17%

10%×1000

10/100×1000=

100

3 0

3 years ago