Chemicals Reaction Online Practice
Which option is an example of a chemical change?
- baking a cake
A scientist is using a lithium ion battery to power her laptop. Which statement about the battery is correct?
-A new substance is formed as the battery is used.
Use the chemical reaction to answer the question.
2H2O2→2H2O +O2
Which statement about the reaction is correct?
-The H2O and O2 produced have the same mass as the original H2O2.
In the compound NH3, how are the atoms likely bonded to one another?
-Each hydrogen shares two electrons with nitrogen.
Which statement correctly explains how matter is conserved in chemical reactions?
-The number of atoms in the reactants is always equal to the number of atoms in the products.
In the formula
1N2 +3H2 → 2NH3 + 1H2
1 diatomic nitrogen (1N2) and 3 diatomic hydrogen (3H2) produce 2 ammonia (2NH3) with 1 diatomic hydrogen (1H2) left over. How can you change the formula so no diatomic hydrogen (H2) is left over?
-Remove a H2 molecule from the left side of the equation.
Suppose 20 atoms of hydrogen (H) react with chlorine (Cl) to produce 20 molecules of hydrochloric acid (HCl). According to the law of conservation of matter, how many atoms of chlorine reacted with the hydrogen?
-20
Which of the following describes what it means for a chemical equation to be balanced?
-It has the same number of atoms on both sides for each specific type of atom.
How many atoms are represented in the formula Na2HPO4?
-eight
Fluorine is in Group 17 of the periodic table. Two fluorine atoms bond to form highly reactive fluorine gas, F2. Which statement about the bond between the fluorine atoms is correct?
-The atoms share two valence electrons.
Use the generalized chemical equation to answer the question.
A + BC → AC + B
Which type of reaction does the generalized equation represent?
-single replacement
Use the equation to answer the question.
A + B → AB
Which type of reaction is modeled by the equation?
-synthesis
Which phrase defines reduction?
-a gain of one or more electrons
Which event occurs during an endothermic reaction?
-Heat and light are absorbed from the environment
Which statement about the reaction that forms water is correct?
-The reaction is exothermic because the total energy released by the products is greater than the energy absorbed in the reactants.
Just answers so it can be faster
- baking a cake
-A new substance is formed as the battery is used.
-The H2O and O2 produced have the same mass as the original H2O2.
-Each hydrogen shares two electrons with nitrogen.
-The number of atoms in the reactants is always equal to the number of atoms in the products.
-Remove a H2 molecule from the left side of the equation.
-20
-It has the same number of atoms on both sides for each specific type of atom.
-eight
-The atoms share two valence electrons.
-single replacement
-synthesis
-a gain of one or more electrons
-Heat and light are absorbed from the environment.
-The reaction is exothermic because the total energy released by the products is greater than the energy absorbed in the reactants.
Baby Jr is correct
Mine has 5 questions
The reaction is exothermic because the water molecules are just really good at making puns and they are always releasing a lot of energy through their jokes. They're quite the comedic duo, H2O and O2!
To determine whether an option is an example of a chemical change, you need to understand the difference between a chemical change and a physical change. A chemical change involves the formation of new substances with different properties, while a physical change only alters the state or appearance of a substance without changing its chemical composition.
In the case of baking a cake, it is an example of a chemical change. When you bake a cake, the ingredients undergo a chemical reaction, resulting in the formation of new substances with different properties, such as the conversion of flour and sugar into carbon dioxide gas, which causes the dough to rise.
In the case of a lithium-ion battery, it does not undergo a chemical change as it is used. The lithium-ion battery operates by the movement of ions between the battery's electrodes and does not undergo a chemical reaction that leads to the formation of new substances.
The chemical equation 2H2O2→2H2O + O2 represents the decomposition of hydrogen peroxide into water and oxygen gas. In this reaction, the mass of the water (H2O) and oxygen gas (O2) produced is equal to the mass of the original hydrogen peroxide (H2O2). Therefore, the statement that the H2O and O2 produced have the same mass as the original H2O2 is correct.
In the compound NH3 (ammonia), the nitrogen atom is likely bonded to each hydrogen atom through a covalent bond. In a covalent bond, atoms share electrons to achieve a stable electron configuration.
The statement that correctly explains how matter is conserved in chemical reactions is that the number of atoms in the reactants is always equal to the number of atoms in the products. This principle is known as the law of conservation of matter, which states that matter cannot be created or destroyed, only rearranged.
To change the formula 1N2 + 3H2 → 2NH3 + 1H2 so that no diatomic hydrogen (H2) is left over, you can remove a H2 molecule from the left side of the equation. The balanced equation would then be:
1N2 + 2H2 → 2NH3
According to the given information that 20 atoms of hydrogen (H) react with chlorine (Cl) to produce 20 molecules of hydrochloric acid (HCl), it means that 20 atoms of chlorine reacted with the hydrogen. This is because for every molecule of hydrochloric acid formed, one atom of chlorine is needed.
A balanced chemical equation refers to having the same number of atoms on both sides of the equation for each specific type of atom. This ensures that matter is conserved in the reaction.
The formula Na2HPO4 contains a total of eight atoms. There are two sodium atoms (Na), two hydrogen atoms (H), one phosphorus atom (P), and four oxygen atoms (O) in the compound.
When two fluorine atoms bond to form highly reactive fluorine gas (F2), they share two valence electrons. This is because fluorine belongs to Group 17 (also known as Group 7A or halogens) of the periodic table, and each atom in this group has seven valence electrons. By sharing two electrons, both fluorine atoms can achieve a stable electron configuration.
The generalized chemical equation A + BC → AC + B represents a single replacement reaction. In this type of reaction, an element (A) reacts with a compound (BC), resulting in the formation of a different element (B) and a different compound (AC).
The equation A + B → AB represents a synthesis reaction. In this type of reaction, two or more substances combine to form a single, more complex substance.
Reduction is defined as a gain of one or more electrons. In chemical reactions, reduction often occurs simultaneously with oxidation, resulting in the transfer of electrons from one substance to another.
During an endothermic reaction, heat and light are absorbed from the environment. Endothermic reactions require an input of energy to proceed and typically feel cold to the touch.
The statement that the reaction forming water is exothermic because the total energy released by the products is greater than the energy absorbed in the reactants is correct. In an exothermic reaction, the products have lower energy than the reactants, and energy is released into the surroundings in the form of heat.