Convection currents occur:
a. Only in liquids
b. When a dense substance is warmer than a less dense substance
c. In both liquids and gases
d. Weakly in solids
Answer:
Jaheem has a goal running a total of 125 miles this month. Each day that he ran, he ran 7 miles. Which expression could Jaheem use to determine how many miles he has left to run after running for d days?
x a.
125 – 7d
x b.
7d + 125
x c. fraction numerator 125 over denominator 7 d end fraction
x d.
7dExplanation:Jaheem has a goal running a total of 125 miles this month. Each day that he ran, he ran 7 miles. Which expression could Jaheem use to determine how many miles he has left to run after running for d days?
x a.
125 – 7d
x b.
7d + 125
x c. fraction numerator 125 over denominator 7 d end fraction
x d.
7d
What what I put to answer this?
Inside a car that was at STP, a 1.39 L bottle warms up to 97 C. If the volume of the bottle remains constant, what is the pressure, in atm,inside the hot water bottle?
Answer:
1.36 atm
Explanation:
We'll begin by converting 97 °C to Kelvin temperature. This can be obtained as follow:
T(K) = T(°C) + 273
T(°C) = 97 °C
T(K) = 97 °C + 273
T(K) = 370 K
Finally, we shall determine the pressure in the hot water bottle. This can be obtained as follow:
Volume = constant
Initial temperature (T₁) = stp = 273 K
Initial pressure (P₁) = 1 atm
Final temperature (T₂) = 370 K
Final pressure (P₂) =?
P₁ / T₁ = P₂ / T₂
1 / 273 = P₂ / 370
Cross multiply
273 × P₂ = 370
Divide both side by 273
P₂ = 370 / 273
P₂ = 1.36 atm
Therefore, the pressure in the hot water bottle is 1.36 atm.
2 A + 4 B → 2 C How many mol of B must react with excess A to produce 2 mol of C?
Answer:
4 mol B
Explanation:
Step 1: Write the balanced generic equation
2 A + 4 B → 2 C
Step 2: Establish the appropriate molar ratio
According to the balanced equation, the molar ratio of B to C is 4:2.
Step 3: Calculate the moles of B needed to produce 2 moles of C
2 mol C × 4 mol B/2 mol C = 4 mol B
5.4 When looking down the C{{TOP-HAT-MATH-TOKEN-0}}-C{{TOP-HAT-MATH-TOKEN-1}} bond in 2,3-dimethylbutane, what is the most stable conformer
Answer:
The most stable conformer would be the anti-conformer when the substituent methyl groups are farthest away from each other.
Explanation:
Isomers are chemical compounds with the same molecular formula but with different molecular structures.
Conformers are a special type of isomers that produce different structures when the substituents of a Carbon-Carbon single bond (C-C) are rotated.
In 2,3 dimethyl butane, the substituent methyl groups are located around the second and third Carbon to Carbon single bond.
To achieve a stable configuration, the methyl group substituents need to be as far apart as possible (that is, in an anti-position) to minimise repulsion.
The closer the methyl groups are to each other, the more they repel each other and the more unstable the conformer becomes.
Given the following information, calculate the density in g/mL of an irregular solid.
Mass of weighing vessel 1.005g
Mass of solid + weighing vessel 9.441g
Volume of liquid in graduated cylinder 3.45 mL
Volume of liquid in graduated cylinder + volume of solid 5.45 mL
Answer:
4.22 g/mL
Explanation:
First we calculate the mass of the solid via mass difference:
Mass of solid = 9.441 g - 1.005 g = 8.436 gThen we calculate the volume of the solid, once again by difference:
Volume of solid = 5.45 mL - 3.45 mL = 2.00 mLFinally we calculate the density in g/mL:
Density = 8.436 g / 2.00 mL = 4.22 g/mLThe density of an irregular solid will be "4.96 g/mL".
According to the question,
→ The Mass of solid will be:
= [tex][(Mass \ of \ solid+ Weighing \ vessel)-(Mass \ of \ weighing)][/tex]
By substituting the values, we get
= [tex]9.441-1.005[/tex]
= [tex]8.436 \ g[/tex]
→ The Volume of solid will be:
= [tex][(Volume \ of \ liquid \ in \ grad. \ cylinder+Solid)-(Volume \ of \ grad. \ cylinder)][/tex]
= [tex]5.15 - 3.45[/tex]
= [tex]1.70 \ mL[/tex]
hence,
→ The density of irregular solid will be:
= [tex]\frac{Mass}{Volume}[/tex]
= [tex]\frac{8.436}{1.70}[/tex]
= [tex]4.96 \ mL[/tex]
Thus the above is the correct answer.
Learn more:
https://brainly.com/question/1150199
The energies of the bonds broken in a certain reaction are greater than the energies of the bonds formed. Which one of the following statements about this reaction must be true?
a. The reaction is endothermic.
b. The reaction is exothermic.
c. The reaction is spontaneous.
d. The reaction is non-spontaneous.
Answer:
a. The reaction is endothermic.
Explanation:
The heat involved in a chemical reaction is given by the enthalpy change (ΔH), which is equal to the balance between the chemical bonds that are broken (release energy) and the chemical bonds that are formed (need energy):
ΔH ≅ bonds broken - bonds formed
If broken bonds > bonds formed ⇒ ΔH > 0 ⇒ endothermic reaction
Therefore, the reaction is endothermic (it requires energy).
If 20.0 mLmL of a 0.100 NN acid solution is needed to reach the end point in titration of 32.5 mLmL of a base solution, what is the normality of the base solution
Answer:
The correct answer is "0.051 N".
Explanation:
Given
Volume,
[tex]V_1=20.0 \ mL[/tex]
[tex]V_2=32.5 \ mL[/tex]
Normality,
[tex]N_1=0.1 \ N[/tex]
[tex]N_2=?[/tex]
As we know,
⇒ [tex]N_1V_1=N_2V_2[/tex]
or,
⇒ [tex]N_2=\frac{N_1V_1}{V_2}[/tex]
On putting the values, we get
⇒ [tex]=\frac{0.1\times 20.0}{32.5}[/tex]
⇒ [tex]=\frac{2}{32.5}[/tex]
⇒ [tex]=0.051 \ N[/tex]
An atom has nine protons and ten electrons. This makes it:
An alpha particle
Neutrally charged
An ion
A cathode ray
Nonstoichiometric
Answer:
C: Ion
Explanation:
We are told that the atom has;
9 protons
10 electrons.
Now, in chemistry, when number of electrons(negative) is more than number of protons(positive), we say that the atom is negatively charged.
Now, looking at the options;
- alpha particles have 2 protons and 2 neutrons and so it is not correct
- for an atom to be neutrally charged, number of protons must be equal to number of electrons. Thus it is not correct.
- For an atom to be an ion, it means that there is an unequal amount of electrons and protons. If the atom has more electrons than protons, it is called anion(negative ion) but if it has less electrons than protons, it is called cation(positive ion).
Thus, option C is the correct answer.
How many atoms are there in 5.20 mil of hafnium. Please help due in 1hr
A sample of polystyrene, which has a specific heat capacity of , is put into a calorimeter (see sketch at right) that contains of water. The polystyrene sample starts off at and the temperature of the water starts off at . When the temperature of the water stops changing it's . The pressure remains constant at . Calculate the mass of the polystyrene sample. Be sure your answer is rounded to significant digits.
This question is incomplete, the complete question is;
A sample of polystyrene, which has a specific heat capacity of 1.880 J.g⁻¹, is put into a calorimeter (see sketch at right) that contains 300.0 g of water. The polystyrene sample starts off at 94.9 °C and the temperature of the water starts off at 22.0. When the temperature of the water stops changing it's 27 °C . The pressure remains constant at 1 atm.
Calculate the mass of the polystyrene sample. Be sure your answer is rounded to 2 significant digits.
Answer:
the mass of the polystyrene sample is 57 g
Explanation:
Given the data in the question;
mass of water m[tex]_{water[/tex] = 300 g
Temperature of water T[tex]_{water[/tex] = 22 °C
Specific heat capacity of water C[tex]_{water[/tex] = 4.184 J/g°C
mass of the polystyrene sample m[tex]_{polystyrene[/tex] = ?
T[tex]_{polystyrene[/tex] = 94.9 °C
Specific heat capacity of polystyrene; C[tex]_{polystyrene[/tex] = 1.880 J.g⁻¹.°C⁻¹
T = 27.7 °C
Now, using heat conservation equation
heat lost by polystyrene = heat gained by water
m[tex]_{polystyrene[/tex] × C[tex]_{polystyrene[/tex] × ( T[tex]_{polystyrene[/tex] - T ) = m[tex]_{water[/tex] × C[tex]_{water[/tex] × ( T - T[tex]_{water[/tex] )
We substitute
m[tex]_{polystyrene[/tex] × 1.880 × ( 94.9 - 27.7 ) = 300 × 4.184 × ( 27.7 - 22 )
m[tex]_{polystyrene[/tex] × 1.880 × 67.2 = 300 × 4.184 × 5.7
m[tex]_{polystyrene[/tex] × 126.336 = 7154.64
m[tex]_{polystyrene[/tex] = 7154.64 / 126.336
m[tex]_{polystyrene[/tex] = 56.63 ≈ 57 g { 2 significant figures }
Therefore, the mass of the polystyrene sample is 57 g
When does a redox reaction produce electricity?
A. Only when an electrical device is attached
B. Whenever electrons are transferred between atoms
C. When electrons are transfered, and a pathway for electrons is provided
D. Whenever a pathway for electrons is provided
Metallic Bond
When nitrogen shares electrons with oxygen, what kind of bond is made?
Answer: covalent bonds
Explanation:
Show the complete ionic equation and net ionic equation for all the equations below, then state whether or not a precipitate (insoluble compound) will form. To receive full credit, you must show ALL your work.
Cacl2(aq) + K2co3(aq) + -------->
Bacl2(aq) + MgSO4(aq) + -------->
AgNO3(aq) + Kl(aq) →
Nacl(aq) + (NH4)2Cro4(aq) →
Answer:
(a): Precipitate of calcium carbonate will form.
(b): Precipitate of barium sulfate will form.
(c): Precipitate of silver iodide will form.
(d): Precipitate of sodium chromate will form.
Explanation:
Complete ionic equation is defined as the equation in which all the substances that are strong electrolytes present in an aqueous state and are represented in the form of ions.
Net ionic equation is defined as the equations in which spectator ions are not included.
Spectator ions are the ones that are present equally on the reactant and product sides. They do not participate in the reaction.
(a):
The balanced molecular equation is:
[tex]CaCl_2(aq)+K_2CO_3(aq)\rightarrow 2KCl(aq)+CaCO_3(s)[/tex]
The complete ionic equation follows:
[tex]Ca^{2+}(aq)+2Cl^-(aq)+2K^+(aq)+CO_3^{2-}(aq)\rightarrow 2K^+(aq)+2Cl^-(aq)+CaCO_3(s)[/tex]
As potassium and chloride ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3(s)[/tex]
Precipitate of calcium carbonate will form.
(b)
The balanced molecular equation is:
[tex]BaCl_2(aq)+MgSO_4(aq)\rightarrow MgCl_2(aq)+BaSO_4(s)[/tex]
The complete ionic equation follows:
[tex]Ba^{2+}(aq)+2Cl^-(aq)+Mg^{2+}(aq)+SO_4^{2-}(aq)\rightarrow Mg^{2+}(aq)+2Cl^-(aq)+BaSO_4(s)[/tex]
As magnesium and chloride ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Ba^{2+}(aq)+SO_4^{2-}(aq)\rightarrow BaSO_4(s)[/tex]
Precipitate of barium sulfate will form.
(c):
The balanced molecular equation is:
[tex]AgNO_3(aq)+KI(aq)\rightarrow KNO_3(aq)+AgI(s)[/tex]
The complete ionic equation follows:
[tex]Ag^{+}(aq)+NO_3^-(aq)+K^+(aq)+I^{-}(aq)\rightarrow K^+(aq)+NO_3^-(aq)+AgI(s)[/tex]
As potassium and nitrate ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]Ag^{+}(aq)+I^{-}(aq)\rightarrow AgI(s)[/tex]
Precipitate of silver iodide will form.
(d):
The balanced molecular equation is:
[tex]2NaCl(aq)+(NH_4)_2CrO_4(aq)\rightarrow 2NH_4Cl(aq)+Na_2CrO_4(s)[/tex]
The complete ionic equation follows:
[tex]2Na^{+}(aq)+2Cl^-(aq)+2NH_4^+(aq)+CrO_4^{2-}(aq)\rightarrow 2NH_4^+(aq)+2Cl^-(aq)+Na_2CrO_4(s)[/tex]
As ammonium and chloride ions are present on both sides of the reaction. Thus, they are considered spectator ions.
The net ionic equation follows:
[tex]2Na^{+}(aq)+CrO_4^{2-}(aq)\rightarrow Na_2CrO_4(s)[/tex]
Precipitate of sodium chromate will form.
Use the following balanced equation to answer the questions below.
Answer:
A. 4.5 mol Mg(OH)₂
B. 6 mol NaOH
Explanation:
Let's consider the following balanced equation.
Mg(NO₃)₂ + 2 NaOH ⇒ Mg(OH)₂ + 2 NaNO₃
PART A
The molar ratio of NaOH to Mg(OH)₂ is 2:1. The moles of Mg(OH)₂ produced from 9 moles of NaOH are:
9 mol NaOH × 1 mol Mg(OH)₂/2 mol NaOH = 4.5 mol Mg(OH)₂
PART B
The molar ratio of NaOH to NaNO₃ is 2:2. The moles of NaOH needed to produce 6 moles of NaNO₃ are:
6 mol NaNO₃ × 2 mol NaOH/2 mol NaNO₃ = 6 mol NaOH
physical reactions of carbonyl group
Answer:
The polarity of the carbonyl group notably affects the physical properties of melting point and boiling point, solubility, and dipole moment. Hydrocarbons, compounds consisting of only the elements hydrogen and carbon, are essentially nonpolar and thus have low melting and boiling points.
Explanation:
pls mark brainliest and these are my notes from last year.
HCl(aq) and KOH(aq) Express your answer as a balanced chemical equation. Identify all of the phases in your answer.
Answer:
HCl(aq) + KOH(aq)---------->KCl (aq)+ H2O(l)
A length of copper wire has a mass of 9.49. How many moles of copper are in the wire [ ] moles
Answer:
0.149 moles
Explanation:
The problem is asking us to convert 9.49 grams of copper into moles. We can do that by using copper's molar mass:
Molar mass of copper = 63.55 g/molNow we proceed to calculate the number of moles:
9.49 g ÷ 63.55 g/mol = 0.149 molesThere are 0.149 moles of copper in the wire.
write any 5 great scientist name
Albert Einstein
Marie Curie
Isaac Newton
Charles Darwin
Nikola Tesla
Galileo Galilei
Ada Lovelace
Please mark me brainliest!
Albert Einstein Charles Darwin Robert Hooke Issac Newton
Galileo Galilei
water molecules stick to nearby water molecules due to
Answer:
The answer will have to be A
When an ionic compound is created, energy is _________when creating the cation, energy is usually _______ when creating the anion, and energy is _______ when the ionic bond is formed resulting in a net [ Select ] of energy for the entire process of making an ionic compound.
Answer:
Absorbed
Released
Released
Explanation:
The formation of a cation is an endothermic process because energy must be absorbed in order to remove an electron from an atom.
Similarly, energy is evolved when an electron is added to an atom to form a negative ion.
The formation of an ionic compound is an exothermic process. Since ionic compounds are more stable than the individual ions separated by a distance, the excess energy of the isolated ions is evolved when the ionic compound is formed.
Waves conduct energy through
PLS HELP ME WITH THESE QUESTIONS ITS DUE TOMORROW I WILL MARK U AS BRAINLIEST
Answer:
See Explanation
Explanation:
1 mole of Cl2 gas occupies 22.4 L
x moles of Cl2 gas occupies 5.24 L
x= 1 × 5.24/22.4
x= 0.23 moles of Cl2
According to the kinetic theory of gases, the particles of a gas are in constant random motion and collide with each other and the walls of the container. Collision between gas particles are perfectly elastic.
Hence the statement that particles must not be able to move in any fixed or open container is false according to the kinetic theory of gases.
HELP PLZ AND THANKS WILL MARK YOU AS BRAINLIEST
Answer:
D
Explanation:
When a liquid sample is taken from sea level to a higher elevation, what happens to the external (atmospheric) pressure on the liquid and the boiling point of the liquid
Answer:
The external atmospheric pressure decreases and so does the boiling point of the liquid.
Explanation:
We know that pressure decreases with height. Thus atmospheric pressure decreases at higher elevation.
The implication of this is that, if I take a liquid from sea level to a higher elevation, the external atmospheric pressure on the liquid will decrease and so does its boiling point.
Hence, the liquid boils at a lower temperature when placed at a higher elevation. For this reason, the boiling point of a liquid is lower on the mountain.
Explain as to why two hydrogen form H2 molecule but not molecules such as H3, H4 etc..
Hydrogen is a diatomic gas with two atoms (di meaning two). H2 is referred to as molecular hydrogen because hydrogen atoms are covalently joined together to form a molecule.
Because two hydrogen molecules are connected to one other by a covalent connection, hydrogen is denoted as H2.
Hydrogen has only one electron, so to complete its duet(octet in case of nitrogen) it has to bond with another hydrogen molecule to be stable and also exist.
You can remember it like this :
H = element
H2 = gas
Other diatomic gases :
O2 (oxygen)
N2 (nitrogen)
help i’ll give u points
Answer:
60ug
Explanation:
If it has experienced two half lives, that means it has been halved twice. in that case, to undo it, just multiply it by two twice. 0.15ug * 2 = 0.30ug. 0.30ug * 2 = 0.60ug. Hope this helps.
Hydrogen chloride gas and oxygen react to form water vapor and chlorine gas. What volume of chlorine would be produced by this reaction if 7.12 L of oxygen were consumed?
Also, be sure your answer has a unit symbol, and is rounded to 3 significant digits.
Answer:
6
Explanation:
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The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant . Suppose the osmotic pressure of a certain solution is measured to be at an absolute temperature of .
Answer:
c = π/T*R
c = 0.199M
Explanation:
Is measured to be 5.1 atm at an absolute temperature of 312. K. Write an equation that will let you calculate the molarity c of this solution. Your equation should contain only symbols. Be sure you define each symbol other than R.
The osmotic pressure of a solution, π, is defined as:
π = c*T*R
As we know osmotic pressure π = 5.1atm, T = 312K and R = 0.082atmL/molK
we can replace in the equation as follows:
π= c*T*R
c = π/T*Rc = 5.1atm/312K*0.082atmL/molK
c = 0.199M
Which of the following element has the highest ionization energy?
O A. CI
OB. I
O C. F
O D. Br