Pls answer fast. thanks !

Which statement best reflects a change in climate?

zalisa [80]

Answer:

droughts in California have become more common in California

Explanation:

Climate is weather over time which means that the first and the third one are just isolated incidents and the last answer choice shows climate but it doesn't show a change in climate

6 0

2 years ago

HELP NOW BRAINLIST AND 15 POINTS!!!!! I'M TIMIED!!!!!

goblinko [34]

Answer:

Explanation:

1 = The given chemical reaction does not follow the law of conservation of mass because,

2 = Four hydrogen atoms are present in reactant side and two hydrogen atoms are present in product side.

3 = 1 ) The given chemical reaction does not follow the law of conservation of mass because,

CH₄ + O₂ → CO₂ + H₂O

16 g + 32 g 44 g + 18 g

48 g 62 g

Law of conservation of mass:

This law stated that mass can not be created or destroyed in chemical reaction. It just changed from one to another form.

For example:

C₂H₄ + 3O₂ → 2CO₂ + 2H₂O

28 g + 96 g = 88 g + 36 g

124 g = 124 g

6 0

3 years ago

Which orbital has the lowest energy

GalinKa [24]

Answer:

s orbital

Explanation:

it has the lowest energy because

Paulis law state that orbitals with lower energy must be fill first before that of higher energy

and the s orbital is filled first

5 0

2 years ago

Which of the following is an acceptable IUPAC name?(A) 3,6-dimethylheptane (B) 2-ethyl-3-methylheptane (C) 5-methyl-3-ethylhepta

bearhunter [10]

Answer:

D) 4-ethyl-4-methylheptane

Explanation:

The rules for naming of alkanes with substituents.

1. The carbon chain with the maximum number of carbon atoms must be selected as a parent chain.

2.Numbering should be done in such a way that each substituent gets the least number.

3. Substituents whose name comes before the another substituents's name in the English alphabet is written first.

4. Substituents are written first with their location in the chain and the name of the parent chain is done. Numbers are separated from numbers by comma and numbers are separated from letters by using hyphen.

Considering (a) 3,6-dimethylheptane

Violation of Rule - 2 mentioned above

The numbering of the parent chain is not done in a right way. Numbering must be done such that each substituent gets the least number. So, The correct name is 2,5-dimethylheptane

Considering (b) 2-ethyl-3-methylheptane

Violation of Rule - 1 mentioned above.

The carbon chain with the maximum number of carbon atoms must be selected as a parent chain. The parent chain selected is of 7 carbon atoms but the parent chain is of 8 carbon atoms. So, The correct name is 3,4-dimethyloctane

Considering (c) 5-methyl-3-ethylheptane

Violation of Rule - 3 mentioned above.

'e' comes before 'm' . So, ethyl- is written first than methyl- . So, The correct name is 3,6-dimethyloctane

Considering (d) 4-ethyl-4-methylheptane

This is a IUPAC name and following all the rules mentioned above.

3 0

3 years ago

A 0.708 g sample of a metal, M, reacts completely with sulfuric acid according to the reaction M ( s ) + H 2 SO 4 ( aq ) ⟶ MSO 4

ollegr [7]

Answer:

The metal has a molar mass of 65.37 g/mol

Explanation:

Step 1: Data given

Mass of the metal = 0.708 grams

Volume of hydrogen = 275 mL = 0.275 L

Atmospheric pressure = 1.0079 bar = 0.9947 atm

Temperature = 25°C

Vapor pressure of water at 25 °C = 0.03167 bar = 0.03126 atm

Step 2: The balanced equation

M(s) + H2SO4(aq) ⟶ MSO4 (aq) + H2(g)

Step 3: Calculate pH2

Atmospheric pressure = vapor pressure of water + pressure of H2

0.9947 atm = 0.03126 atm + pressure of H2

Pressure of H2 = 0.9947 - 0.03126

Pressure of H2 = 0.96344 atm

Step 4: Calculate moles of H2

p*V=n*R*T

⇒ with p = The pressure of H2 = 0.96344 atm

⇒ with V = the volume of H2 = 0.275 L

⇒ with n = the number of moles H2 = TO BE DETERMINED

⇒ with R = the gas constant = 0.08206 L*atm/K*mol

⇒ with T = the temperature = 25°C = 298 Kelvin

n = (p*V)/(R*T)

n = (0.96344 * 0.275)/(0.08206*298)

n = 0.01083 moles

Step 5: Calculate moles of M

For 1 mole of H2 produced, we need 1 mole M

For 0.0108 moles of H2 we need 0.01083 moles of M

Step 6: Calculate molar mass of M

Molar mass M = Mass M / moles M

Molar mass M = 0.708 grams / 0.01083 moles

Molar mass M = 65.37 g/mol

The metal has a molar mass of 65.37 g/mol

5 0

3 years ago