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-Dominant- [34]
3 years ago
14

Why do lighthouses use lenses?

Chemistry
1 answer:
dolphi86 [110]3 years ago
6 0
To see far away? I'm thinking that like human glasses, lighthouses need lenses to see the far away boats. Or humans.
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Read the given equation:
Assoli18 [71]

Answer:

D.

HCl is acid

Ca(OH)2 is base

CaCl2 is salt

5 0
3 years ago
Calculează masa zaharului si volumul apei necesare pentru prepararea 500g de soluție de zahăr cu partea de masa 20%
Sedbober [7]
T = 20 %  : 20 / 100 = 0.2

m1 = solute 

m2 = Solvent

T = m1 / m1 + m2

0.2 = 500 g / 500 g + m2

0.2 * ( 500 + m2 ) = 500

0.2 * 500 + 0.2 m2 = 500

100 + 0.2 m2 = 500

0.2 m2 = 500 - 100

0.2 m2 = 400

m2 = 400 / 0.2

m2 = 2000 g of water

hope this helps!



7 0
4 years ago
Assuming that all the energy given off in the reaction goes to heating up only the air in the house, determine the mass of metha
nirvana33 [79]

Answer:

0.92 kg

Explanation:

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The moles of air are:

3.9 \times 10^{6} L \times \frac{1.00mol}{22.4L} =1.7 \times 10^{5}mol

The heat required to heat the air by 10.0 °C (or 10.0 K) is:

1.7 \times 10^{5}mol \times \frac{30J}{K.mol} \times 10.0 K = 5.1 \times 10^{7}J

Methane's heat of combustion is 55.5 MJ/kg. The mass of methane required to heat the air is:

5.1 \times 10^{7}J \times \frac{1kgCH_{4}}{55.5 \times 10^{6} J } =0.92kgCH_{4}

3 0
3 years ago
What is the molarity of a KOH solution if it requires 20 milliters of 2.0m HCL to exactcly neutalize 20 milliters of the KOH sol
soldier1979 [14.2K]
HCL 2.0x 3.6790= KOH SOLITION
6 0
3 years ago
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What kind of chemical reaction does the chemical equation sodium + chlorine → sodium chloride represent?
scoundrel [369]
<span>The answer is synthesis. This is a kind of reaction in which numerous reactants mix to make a single product. Synthesis responses discharge energy in the way of heat and light, so they are exothermic. An instance of a synthesis reaction is the creation of water from hydrogen and oxygen.</span>
6 0
3 years ago
Read 2 more answers
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