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Tom [10]
3 years ago
12

How many years ago were seven score and four years ago? (a score means 20)

Chemistry
1 answer:
Zina [86]3 years ago
6 0

144 years, its simple math?

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in heating a kettle of water on an electric stove, 3.34×10^3 J of thermal energy was provided by the element of the stove. yet,
insens350 [35]

Answer:

The percentage efficiency of the electrical element is approximately 82.186%

Explanation:

The given parameters are;

The thermal energy provided by the stove element, H_{supplied} = 3.34 × 10³ J

The amount thermal energy gained by the kettle, H_{absorbed}  = 5.95 × 10² J

The percentage efficiency of the electrical element in heating the kettle of water, η%, is given as follows;

\eta \% = \dfrac{H_{supplied} - H_{absorbed} }{H_{supplied}}  \times 100

Therefore, we get;

\eta \% = \dfrac{3.34 \times 10^3 - 5.95 \times 10^2}{3.34 \times 10^3}  \times 100 = \dfrac{549}{668} \times 100 \approx 82.186 \%

The percentage efficiency of the electrical element, η% ≈ 82.186%.

4 0
3 years ago
What geometry does VSEPR predict for the central atom in NCl3
Archy [21]

Answer:

Tetrahedral electron geometry and trigonal pyramidal molecular geometry.

Explanation:

The Lewis structure is shown in Figure 1.

The central N atom has three bonding pairs and one lone pair, for <em>four electron groups</em>.

VSEPR theory predicts a tetrahedral electron geometry with bond angles of 109.5°.

We do not count the lone pair in determining the molecular shape.

The molecular geometry is trigonal pyramidal (see Figure 2).

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Please answer fast, I will give brainliest if correct!
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Answer:

Explanation: 30 min

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write an activity to show the change in state and change in temperature during a chemical reaction(change)
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If a piece of charcoal is taken and set on fire it will evolve CO2 and heat. Charcoal is solid but carbon dioxide is gaseous. This is an example of change of state and evolve of heat during chemical reaction.
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For Neutron it’s supposed to be 36 right ?
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I believe so..... hmm idk
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