Heating Food
This packaged meal, often used by the military, is shortened to MRE.
What is a Meal, Ready-to-Eat?
These are the starting substances in a chemical reaction.
What are reactants?
This tool measures temperature during an investigation.
What is a thermometer?
This word compares the amounts of two reactants. A common cooking example of this would be 1 cup of water for every 2 cups of rice.
What is a ratio?
Measurements and observations that support a claim are called this.
What is evidence?
Add this liquid to activate an MRE flameless heater.
What is water?
A chemical reaction rearranges atoms to form new _________.
What are substances or products?
A mixture starts at 22°C and reaches 37°C. Calculate its temperature increase.
What is 15°C?
A mixture contains 2 grams of A and 8 grams of B. Which reactant makes up the larger percentage?
What is reactant B?
After mixing substances, scientists identify a new substance. This supports the claim that this kind of reaction occurred.
What is a chemical reaction?
During a power outage, an MRE warms food without electricity or this other common source of heat.
What is an open flame or fire?
Thermal energy moves from warmer objects to _________ objects.
What is cooler or cold objects?
A mixture starts at 22°C and cools to 17°C. Calculate the temperature change.
What is −5°C or a decrease of 5°C?
A mixture has 5 g of A and 15 g of B. This is its total mass.
What is 20 g?
A reaction mixture is colder than the room. Between these two systems, thermal energy transfers in this direction.
What is from the warmer room to the colder mixture?
A labeled drawing showing the food, heater, and energy arrows is this scientific tool.
What is a model?
An air-activated hand warmer needs this gas from the air to react with its iron.
What is oxygen?
Three mixtures start at 20°C.
A peaks at 28°C
B at 43°C
C at 35°C
Which mixture has the largest rise?
What is mixture B? It rises 23°C
A mixture contains 4 grams of A and 16 grams of B. What percent of the mixture is A?
Hint: Percentage = (Part / Whole) × 100
What is 20%?
A heater must cost at most $5 and raise a model temperature at least 15°C. Heater A costs $4 and raises it 16°C; Heater B costs $6 and raises it 20°C. This heater meets both requirements.
What is heater A?
The chemicals in an MRE or flameless heater never touch the meal, yet it warms. How is this possible?
Energy/heat transfers from the heater through the container into the food.
A cup gets warm in sunlight. What is one piece of evidence you could use to prove a chemical reaction has not occurred?
What is no new substances were formed?
When comparing reaction mixtures, what are two things that we can keep the same across each mixture to ensure that our comparisons are fair?
What are total mass, starting temperature, container, room conditions, or measurement times?
A mixture has 5 g of A and 15 g of B. What percent of the total mixture is A?
Hint: Percentage = (Part / Whole) × 100
What is 25%?
True or false. If an MRE heater reaches 60°C, the food I am heating will also reach 60°C
What is false?