When patterns of stars appear to move across the sky, it provides evidence that ________.

A. Earth and stars move together
B. Earth rotates in space
C. patterns of stars can change
D. stars actually move

Answer:

2Na + 2H20--> 2NaOH+H2

............. this is the ans

Answer:

It partially ionizes

Explanation:

Higher tier) Weak acids only partially ionise in water. Only a small fraction of their molecules break into hydrogen ions when added to water.

The Balanced chemical equation for above reaction will be :

[tex] \small{ \mathrm{3NaBr + H_3PO_4 \rightarrow Na_3PO_4 + 3HBr}}[/tex]

The Coefficients will be :

So, Correct option is :

A. 3, 1, 1, 3

_____________________________

[tex]\mathrm{ \#TeeNForeveR}[/tex]

Answer:

Potassium Bromide

Explanation:

not sure but i think thats it

Answer:

0.021

Explanation:

that's the answer because I just did an exam that included this question and then the miss explained to me why this was the answer, but don't worry am 100% sure the answer is 0.021 .

The mole fraction of ethanol in a solution of 47.5 g of ethanol in 850 g of water is 0.021.

Mole fraction of any substance present in solution will be calculted by dividing the moles of sample to the total moles of solution.

Moles will be calculated as:

n = W/M , where

W = given mass

M = molar mass

Moles of ethanol will be calculated as:

n = 47.5g / 46.07g/mol = 1.03 moles

Moles of water will be calculated as:
850g / 18g/mol = 47.18 moles

Total moles of solution = 1.03 + 47.18 = 48.21 moles

Mole fraction of ethanol in water will be calculated as:

mole fraction = 1.03 / 48.21 = 0.021

Hence, mole fraction is 0.021.

To know more about mole fraction, visit the below link:

https://brainly.com/question/25468666

Answer:

7200 kPa

Explanation:

Applying,

PV/T = P'V'/T'................ Equation 1

Where P = Initial pressure of neon gas, V = Initial volume of neon gas, T = Initial temperature of neon gas, P' = Final pressure of neon gas, V' = Final volume of neon gas, T' = Final Temperature of neon gas

Make P' the subject of the equation

P' = PVT'/V'T.............. Equation 2

Given: P = 900 kPa, V = 8.0 L, T = 300 K, V' = 2.0 L, T' = 600 K

Substitute these values into equation 2

P' = (900×8×600)/(2×300)

P' = 7200 kPa

Answer:

600.7 moles

Explanation:

Applying,

PV = nRT................... Equation 1

Where P = Pressure of oxygen, V = Volume of oxygen, n = number of moles, R = molar gas constant, T = Temperature.

make n the subject of the equation

n = PV/RT............... Equation 2

From the question,

Given: P = 190 atm, V = 35 L, T = 135 K

Constant: R = 0.082 atm.dm³/K.mol

Substitute these values into equation 2

n = (190×35)/(135×0.082)

n = 600.7 moles of xygen

Answer:

:D

Explanation:

8. D. All of the above

9. C. Mechanical weathering

10. D. All of the above

Answer:

8. D

9. A

10. D

(D)

Explanation:

On the left side two molecules, each made of 2 grays and 3 blues, which suggests that only (D) offers the right combination: 2 Al atoms and 3 O atoms that make up Al2O3.

Answer:

See Explanation

Explanation:

Volume of base used  = (31.79 - 1.6) + (32.12 - 0.98) + (42.87 -13.21)/3 = 30.34 cm3

Volume of acid used = (24.86 - 0.42) + (24.11 - 0.11) + (27.67 -3.42)/3 = 24.23 cm3

For trial 1= number of moles of HBr = 24.44/1000 * 0.3 = 0.0073 moles

For trial 2= number of moles of HBr = 24/1000 * 0.3 = 0.0072 moles

For trial 3= number of moles of HBr = 0.0089 moles

HBr(aq) + KOH(aq) -----> KBr(aq) + H2O(l)

One mole of base is required to neutralize one mole of acid.

From CAVA/CBVB =nA/nB

CAVAnB = CBVBnA

CB = CAVAnB/VBnA

CB = 0.3 * 24.23 * 1/30.34  * 1

CB = 0.24 moldm-3

number of moles of KOH = concentration * volume

number of moles = mass/molar mass

molar mass of KOH = 56 g/mol

mass/56 =  0.24 * 30.34/1000

mass = 0.24 * 30.34/1000 * 56

mass =0.408 g of KOH

Answer:

0.075 moles of iron oxide would be produced by complete reaction of 0.15  moles of iron.

Explanation:

The balanced reaction is:

4 Fe + 3 O₂ → 2 Fe₂O₃

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

You can apply the following rule of three: if by stoichiometry 4 moles of Fe produce 2 moles of Fe₂O₃, 0.15 moles of Fe produce how many moles of Fe₂O₃?

[tex]moles of Fe_{2} O_{3} =\frac{0.15 moles of Fe*2 moles of Fe_{2} O_{3} }{4 moles of Fe}[/tex]

moles of Fe₂O₃= 0.075

0.075 moles of iron oxide would be produced by complete reaction of 0.15  moles of iron.

Answer:

c. Ca(OH)2

Explanation:

I took the test ;)

In chemistry, bases are substances that react with an acid to yield salt. Calcium hydroxide (Ca(OH)₂) is a base as it is a hydroxide of metal. Thus, option c is correct.

Bases are solutes that react with acidic substances to produce water and salt. It comprises substances with hydroxide ion that reacts with hydrogen ion of acid to complete the neutralization reaction.

The carbonates, oxides, and hydroxides of metals make the base that has a pH range of below 7 up to 14. The alkalinity of the substance depends on the ability to release the hydroxide ions in the solution.

Calcium hydroxide (Ca(OH)₂) is a base as it contains OH⁻ ions that are characteristic of bases. On the other hand, NaCl is salt and HF is an acid.

Therefore, Ca(OH)₂ is a base.

Learn more about base here:

https://brainly.com/question/8069088

#SPJ5

Answer:

sodium phosphide!!!!!!!!!!!!!!!

Answer:

1. Allele for shortness (t)

2. Allele for tallness (T)

Explanation:

Gregor Mendel performed numerous experiments using pea plants (Pisium sativum). He tested the height traits of pea plants by crossing tall pea plants (TT) and short pea plants (tt) to obtain offsprings that were all tall (Tt) in the first filial generation (F1).

This is possible because the allele for tallness is DOMINANT while the allele for shortness is RECESSIVE. This means that tallness allele (T) will mask the phenotypic expression of shortness allele (t) when in an heterozygous state (Tt) as in the F1 generation.

Answer:

practise, because it helps you get comfortable in speaking english

and there is also a quote that says "practise makes perfect"

Explanation:

HOPE IT HELPS

Answer:

d. Two moles of carbon dioxide were produced from this reaction

Explanation:

The given chemical reaction can be written as follows;

2C₂H₂ + 5O₂ → 4CO₂ + 2H₂O

From the above chemical reaction, we have;

Two moles of C₂H₂ reacts with five moles of O₂ to produce four moles of CO₂ and two moles of H₂O

We have;

One mole of C₂H₂ will react with two and half moles of O₂ to produce two moles of CO₂ and one mole of H₂O

Therefore, in the above reaction, when one mole of C₂H₂ is used, two moles of CO₂ will be produced.

Answer:

0.11 moles

Explanation:

The equation of the reaction is;

2SO2 + O2 ------>2SO3

Number of moles of O2 in 3.42 g = 3.42g/32 g/mol = 0.11 moles

Hence, 0.11 moles of O2 is consumed when 3.42 g of O2 reacts with SO2 to form SO3.

The pressure inside the television tube containing 2×10¯⁵ g of N₂ at 22 °C is 4.94×10¯⁶ atm

Mole = mass / molar mass

Mole of N₂ =  2×10¯⁵ / 28

Mole of N₂ = 7.14×10¯⁷ mole

The pressure inside the television tube can be obtained by using the ideal gas equation as follow:

PV = nRT

Divide both side by V

P = nRT / V

P = (7.14×10¯⁷ × 0.0821 × 295) / 3.5

P = 4.94×10¯⁶ atm

Learn more about ideal gas equation:

https://brainly.com/question/4147359

Answer:

2. 16.4 L

3. 243.6K

4. 0.25mol

Explanation:

Using the ideal gas formula for the series of questions in this case, we have;

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (K)

QUESTION 2:

V = ?

P = 5 atm

n = 3 mol

T = 60°C = 60 + 273 = 333K

PV = nRT

5 × V = 3 × 0.0821 × 333

5V = 82.02

V = 82.02/5

V = 16.4 L

QUESTION 3:

P = 4 atm

V = 7.5L

n = 1.5mol

T = ?

PV = nRT

4 × 7.5 = 1.5 × 0.0821 × T

30 = 0.123T

T = 30/0.123

T = 243.6K

QUESTION 4:

P = 2.00 atm

V = 3L

n = ?

T = 25°C = 25 + 273 = 298K

PV = nRT

2 × 3 = n × 0.0821 × 298

6 = 24.47n

n = 6/24.47

n = 0.25mol

Answer: the answer is a

Explanation:

always eat fresh fruits and veggiies.

Answer: [tex]49.7\ cm^3[/tex]

Explanation:

Given

At temperature [tex]T_1=289\ K[/tex]

Volume is [tex]V_1=42\ cm^3[/tex]

and the temperature changes to [tex]T_2=342\ K[/tex]

At this temperature volume is [tex]V_2[/tex]

Consider Pressure remains the constant

[tex]\therefore \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\\\\\Rightarrow V_2=V_1\times \dfrac{T_2}{T_1}\\\\\text{Insert values}\\\\\Rightarrow V_2=42\times \dfrac{342}{289}\\\\\Rightarrow V_2=49.7\ cm^3[/tex]

The volume at this temperature is [tex]49.7\ cm^3[/tex]

Answer:When two plates travel in the same direction, they intersect or collide. A convergent boundary is a collision between two plates that are traveling in the same direction. Large damaging earthquakes occur from the collision. The forming of massive folded mountains occurs as two continental plates collide.

Explanation:

Answer:

This natural gas deposit contains 1,300,813.008 moles.

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P * V = n * R * T

In this case:

Replacing:

15 atm* 2.24*10⁶ L= n*0.082 [tex]\frac{atm*L}{mol*K}[/tex]* 315 K

Solving:

[tex]n=\frac{15 atm* 2.24*10^{6}L }{0.082\frac{atm*L}{mol*K}*315 K}[/tex]

n=1,300,813.008 moles

This natural gas deposit contains 1,300,813.008 moles.

The presence of rust in the water of Westfield is the reason for the change in colour.

The water of Westfield has reddish-brown substance. This reddish brown substance in the water is the rust which formed due to the chemical reaction between the iron pipes and the fertilizer substance present in the water.

Due to this reaction, the colour of Westfield's water is different from normal type of water so we can conclude that the presence of rust in the water of Westfield is the reason for the change in colour.

Learn more about rust here: https://brainly.com/question/1477535