Indicate whether each of these reactions is endothermic or exothermic.
NH4CI(S) - NHA" (aq) + Cl(aq) AHxn = 14.7 kJ
NaOH(s) Nat(aq) + OH (aq) AHixo = -44.5 kJ
CH2(g) + 2O2(g) CO2(g) + 2H20(g) Hrxn < 0
CH3COOH(aq) + NaHCO3(s) + CO2(g) + H2O(l) + Na"(aq) + CH3COO(aq)
AHxn > 0

Answer:

The correct answer to the following question will be Option A (Microwaves).

Explanation:

The other given choices are not related to the given circumstances. So that option A seems to be the appropriate one.

Answer:

its a

Explanation:

Answer: Payback time = 0.0075

Explanation: Since payback time is calculated as:

payback time = [tex]\frac{installation cost}{annual savings}[/tex]

First determine the installation cost:

100 mm thick insulation covers 8.3 m². Then 300 mm covers 24.9 m².

To cover 8.3m² costs £20. Then, the cost to cover 24.9 m² is:

cost = [tex]\frac{20*24.9}{8.3}[/tex]

cost = £60

The cost of putting the insulation is £120, so the total cost is:

total cost = £60 + £120

total cost = £180

Savings per year per 100 mm thick is £80. For 300 mm, the value of annual savings is:

savings = [tex]\frac{300*80}{100}[/tex]

savings = 240

payback time = [tex]\frac{installation cost}{annual savings}[/tex]

payback time = [tex]\frac{180}{240}[/tex]

payback time = 0.75

Answer:

Heating Fan is 75.33% efficient.

Explanation:

As it is mentioned that the given fan is a HEATING FAN, it means the it is used for provided heat (thermal energy) to the surrounding. Hence, its efficiency depends upon how much heat/thermal energy is provides.

We can state that.

Total Energy provided = 150 J

Useful Energy = 113 J

Wasted Energy = 37 J

The efficiency of the heating fan can be given by following formula:

Efficiency = ( Useful Energy / Total Energy ) × 100

Efficiency = ( 113 J / 150 J) × 100

Efficiency = (0.7533)× 100

Efficiency = 75.33%

Answer:

it is when a state in which opposing forces or influences are balanced.

A example of equilibrium is in economics  supply and demand are equal.

Explanation:

Answer:

Compromise of 1850

Explanation:

Answer:A

Explanation: Were there any living organisms is the answer because physics is the study of matter,its motion and behaviour of space and time and some other topics like energy and force.

Answer:

B

Explanation:

Forces and vectors on a probe are a physics thing

Answer: D

Explanation:

The statement that describes the effect of large asteroid and comet impacts is they may kick up dust and pollute Earth’s atmosphere. The correct option is D.

Asteroids are the small, big rocks that are made up of dust, and rocks. They orbit the sun and are smaller than a planet. An asteroid hits the earth like 65 million years ago. When asteroids and comets hit the earth's surface, they create large or small craters.

Comets are small or large snowy balls of gases. They are made up of rocks, and dust, and they orbit the sun. They orbit the sun. A comet has three parts, a nucleus, a comma, and a tail. When it comes near the sun, it converts into a burning ball of gases.

Thus, the correct option is D. They may cause small craters on Earth’s surface.

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Answer:

The biological sample that pregnancy tests use to detect pregnancy is urine

Answer:

yes

Explanation:

the urine in the the tester will find hormones to determine if pregnant or not

Answer:

carborane

Explanation:

Carborane acid is the strongest acid in the word. It is minimum 1 million times stronger or harder than 100% sulfuric acid with respect to Hammett acid feature

The pH value of the carborane is -18. Plus it is noncorrosive as it would be handled with bare skin

Therefore in the given case, the carborane is the strongest acid among all available ones

Answer:

Those people could sustain on Mars, by living closer to the poles

Explanation:

As it is given that caps involve the water ice instead of the carbon dioxide

And, current observations of spectrum analyzed that the polar caps are totally different from one other i.e northern one involves more water ice while on the other hand,  the southern one involves most of the carbon dioxide

Moreover, the astronomers unable to see to spectrum portions as the atmosphere absorbs the wavelength

So we conclude that the people could survive on mars if they live near to poles

Explanation:

the last CH2 should CH3

because the first and last carbons are bonded to three hydrogens

The required  complete ionic equation of the reaction

Pb(NO3)2+2KI---->PbI2+2KNO3   is   Pb2+(aq) + 2 I−(aq) → PbI2(s)

A chemical equation in which the electrolytes in aqueous solution are expressed as dissociated ions.

Spectator ions in above equation are as follows- K +and NO3−

Define spectator ions.

Ions that are not involved in the actual chemical reaction are called spectator ions.

Net ionic equation of given reaction isPb⁺²+2I ⁻¹⟶PbI₂It shows only the ions which involves in the chemical reaction.

Therefore, K⁺ and NO3⁻ are spectator ions.

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Answer:Drinking straw

Explanation: my quiz said so

The object that represents the best model of one of the phloem cells is the drinking straw.

Phloem may be defined as a type of vascular tissue in plants that significantly conducts the passage of sugars and other metabolic products from the leaves to the roots. This mediates the migration of sugar which is synthesized in the leaves during photosynthesis.

Apart from this, the phloem also regulates the movement of nutrients from the roots to the upper part of the body. This function of phloem cells shares homology with the object known as a drinking straw that mediates the transport of any fluid in both directions.

Therefore, a drinking straw is an object that represents the best model of one of the phloem cells.

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Your question seems incomplete. The most probable complete question is as follows:

Answer:

Explanation:

its true

hope this helps

plz mark as brainliest!!!!!

Answer:

True

Explanation:

Answer:

Kinetic energy of boy just before hitting the ground is [tex]\approx[/tex]1000 J.

Speed of boy just before hitting the ground is 7.67 m/s

or 17.16 mi/hr.

Explanation:

Given that:

Mass of boy = 75lb = 34 kg

Height, h = 10ft = 3m

To find:

Kinetic energy of boy when he hits the ground.

As per law of conservation of energy The potential energy gets converted to kinetic energy.

[tex]\therefore[/tex] Kinetic energy at the time boy hits the ground = Initial potential energy of the boy when he was at the Height 'h'

The formula for potential energy is given as:

[tex]PE = mgh[/tex]

Where m is the mass

g is the acceleration due to gravity, g = 9.8 [tex]m/s^2[/tex]

h is the height of object

Putting all the values:

PE = [tex]34 \times 9.8 \times 3 \approx 1000\ J[/tex]

Hence, Kinetic energy is [tex]\approx[/tex]1000 J.

Formula for Kinetic energy is:

[tex]KE = \dfrac{1}{2}mv^2[/tex]

where m is the mass and

v is the speed

Putting the values and finding v:

[tex]1000 = \dfrac{1}{2}\times 34 \times v^2\\\Rightarrow v^2 = 58.82\\\Rightarrow v = 7.67\ m/s[/tex]

Given that:

1 m = 1.094 yd and 1 mi = 1760 yd

[tex]\Rightarrow 1609\ m = 1\ mi[/tex]

Converting 7.67 m/s to miles/hour:

[tex]\dfrac{7.67 \times 3600}{1609}=17.16\ mi/h[/tex]

Answer:

Neon and Methane

Explanation:

Nitrogen and Oxygen made up way over half of the atmosphere so it's without a doubt, not those two. Precisely, Nitrogen makes up 78% of the atmosphere while oxygen makes up 21%

Answer: neon and methane

Answer:

[tex]\large \boxed{\text{104 kPa}}[/tex]

Explanation:

To solve this problem, we can use the Combined Gas Laws:

[tex]\dfrac{p_{1}V_{1} }{n_{1}T_{1}} = \dfrac{p_{2}V_{2} }{n_{2}T_{2}}[/tex]

Data:

p₁ = 748 kPa;  V₁ =   273 m³;  n₁ = n₁;  T₁ =  525 K

p₂ = ?;             V₂ = 1100. m³; n₂ =  n₁; T₂ =  293 K

Calculations:

[tex]\begin{array}{rcl}\dfrac{p_{1}V_{1}}{n_{1} T_{1}} & = & \dfrac{p_{2}V_{2}}{n_{2} T_{2}}\\\\\dfrac{\text{748 kPa}\times \text{273 m}^{3}}{n _{1}\times \text{525 K}} & = &\dfrac{p_{2}\times \text{1100. m}^{3}}{n _{1}\times \text{293 K}}\\\\\text{390.0 kPa} & = &3.754{p_{2}}\\p_{2} & = & \dfrac{\text{390.0 kPa}}{3.754}\\\\ & = & \textbf{104 kPa} \\\end{array}\\\text{The new pressure is $\large \boxed{\textbf{104 kPa}}$}[/tex]

Answer:

the molecular formula is CO2

The bond formed is covalent bond

CO2+H2O = H2CO3

The reaction between the compound and water will give us carbonic acid (H2CO3)

Explanation:

density = mass/volume

density = 89.6/10

density = 8.96g/cm³

Answer:

Water cycle

Explanation:

The water cycle, also called as the hydrologic cycle that describes the continual flow of water i.e on over and beyond the surface of the Earth.

The nutrient cycle refers to the cycle in which there is a movement and exchange of organic and inorganic matter

Therefore the water cycle is not a nutrient cycle and hence the same is to be considered

Answer:

water cycle

Explanation:

:)

Answer:

D)It will lead to forced migration.

Explanation:

Forced migration is an involuntary, sudden movement of organisms from one geographical location to another. This is often in response to short term environmental changes such as drought, famine, etc

When an ecosystem suddenly comes under stress due to these short term environmental changes, organisms may not be left with any other choice but to move or go to new locations in the quest for survival. The organisms may not have left the ecosystem in the absence of such short term ecological stress. This is what is meant by forced migration.

Answer:

D forced migration

Explanation:

Answer:-1222kj

Explanation:

Based on the bond energies, the reaction HC≡CH(g) + 5/2 O₂(g) → 2 CO₂(g) + H₂O(g) has a standard enthalpy of reaction of -1222 kJ/mol.

Let's consider the following reaction.

HC≡CH(g) + 5/2 O₂(g) → 2 CO₂(g) + H₂O(g)

Given the bond energies (E), we can calculate the standard enthalpy of the reaction (ΔH°rxn) using the following expression.

[tex]\Delta H\° _{rxn} = E(broken\ bonds) - E(formed\ bonds)[/tex]

The broken bonds are:

 HC≡CH

  O₂

The formed bonds are:

  CO₂

  H₂O

[tex]\Delta H\°_{rxn} = E(C\equiv C) + 2 E(C-H) + 5/2 E(O=O) - 4 E(C=O) - 2 E(O-H)\\\\\Delta H\°_{rxn} = 835kJ/mol + 2 (411kJ/mol) + 5/2 (494kJ/mol) - 4 (799kJ/mol) - 2 (459kJ/mol) = -1222 kJ/mol[/tex]

Based on the bond energies, the reaction HC≡CH(g) + 5/2 O₂(g) → 2 CO₂(g) + H₂O(g) has a standard enthalpy of reaction of -1222 kJ/mol.

Learn more: https://brainly.com/question/24857760

Answer:

mass of carbon = 0.438g

Explanation:

mass percentage = 0.00438%

Answer :

43.8% on edge

hope this helps and good luck!

Answer:

172.385 g/mol

Explanation:

Magnesium Tartrate is C4H4MgO6

C - 12.01 g/mol

H - 1.01 g/mol

Mg - 24.305 g/mol

O - 16.00 g/mol

12.01(4) + 1.01(4) + 24.305 + 16(6) = 172.385 g/mol

Answer:

172.38

Explanation:

[tex]C_4H_4MgO_6\\C=12.01\\H=1.01\\Mg=24.30\\O=16.00\\\\4(12.01)+4(1.01)+24.30+6(16.00)\\48.04+4.04+24.30+96\\=172.38[/tex]

C = 12.01

H=1.01

Mg=24.30

O =16.00

4(12.01)+4(1.01)+24.30+6(16.00)

48.04 +4.04+24.30+96

=172.38

Answer:

The answer is B

Explanation:

When water freezes, the temperature decreases and therefore, the average kinetic energy will decrease as well.

Answer:

[tex]L_{\text{fusion}[/tex] is latent heat of fusion.

Explanation:

[tex]Q=mL_{\text{fusion}}[/tex]

Here,

m is mass of substance

[tex]L_{\text{fusion}[/tex] is latent heat of fusion.

Answer:

"The strength of ionization decreases as the proportion including its protons to the excited electrons" is the right solution.

Explanation:

This question seems incomplete. I believe the answer choices are as followed:

O The ionization energy decreases because the ratio of the protons to electrons increases.

O The ionization energy increases because the ratio of the protons to electrons increases.

O The ionization energy decreases because the ratio of the protons to electrons decreases.

O The ionization energy increases because the ratio of the protons to electrons decreases.

The answer to this is The ionization energy increases because the ratio of the protons to electrons increases. (2nd option).

Answer:

[tex]1.63 \times {10}^{24} [/tex]

one atom of an element = 6.02 \times {10}^{23} atom

The mass of one atom of sulphur = 32g

The mass of one atom of aluminium = 27g

so one atom of aluminium = 6.02 \times {10}^{23}

27g of AL = 6.02 \times {10}^{23} atom

2.70g of AL = X atoms

Then you cross multiply ........

and get the answer

.

Answer:

Vertically Shrunk by a factor of 1/6

Explanation:

Parent Formula: f(x) = a(bx - c) + d

a - vertical shrink/stretch and x-reflections

b - horizontal shrink/stretch and y-reflections

c - horizontal movement left/right

d - vertical movement up/down

Since we are only modifying a, we are dealing with vertical shrink/stretch:

Since a < 1 (1/6 < 1), we are dealing with a vertical shrink of 1/6.

Since a > 0 (1/6 > 0), we do not have a reflection over the x-axis.

Answer:Vertically compressed by a factor of 6

Explanation:

Answer:

When volume is kept constant (kept the same), Gay-Lussac's law states that the pressure of gas varies directly with the temperature of the gas. The equation would be [tex]\frac{P1}{T1}=\frac{P2}{T2}[/tex], Where P is the pressure (in atm) and T is the temperature (in K°).

Explanation:

Answer:

When volume is kept constant (kept the same), Gay-Lussac's law states that the pressure of gas varies directly with the temperature of the gas. The equation would be , Where P is the pressure (in atm) and T is the temperature (in K°).

Explanation:

Answer:

See Explanaton

Explanation:

The law of multiple proportions states that when two same elements form more than a compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.

Oxide A

3.50g of sulphur combined with 6.00g of oxygen

Oxygen:Sulphur = 6 : 3.5

Oxide B

2.80g of sulphur combined with 9.55g

Oxygen : Sulphur = 9.55 : 2.8

Therefore:

The ratio of Oxygen to Sulphur in Oxides A and B is:

[tex]\dfrac{\text{Oxygen}}{\text{Sulphur}} \implies \dfrac{6}{3.5}:\dfrac{9.55}{2.8} = \dfrac{1.7}{1}:\dfrac{3.4}{1}=1:2[/tex]

Ratio of Oxygen=1:2

There is exactly twice in Oxide B as in Oxide A.

This result illustrates the law of multiple proportions.